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1.1.1.5 root 1: .\" Copyright (c) 1991, 1992, 1993 Free Software Foundation -*-Text-*- 1.1 root 2: .\" See section COPYING for conditions for redistribution 1.1.1.6 ! root 3: .\" ! 4: .\" Set up \*(lq, \*(rq if -man hasn't already set it up. ! 5: .if @@\*(lq@ \{\ ! 6: . ds lq " ! 7: . if t .ds lq `` ! 8: . if !@@\(lq@ .ds lq "\(lq ! 9: .\} ! 10: .if @@\*(rq@ \{\ ! 11: . ds rq " ! 12: . if t .ds rq '' ! 13: . if !@@\(rq@ .ds rq "\(rq ! 14: .\} ! 15: .de Id ! 16: .ds Rv \\$3 ! 17: .ds Dt \\$4 1.1 root 18: .. 1.1.1.6 ! root 19: .de Sp ! 20: .if n .sp ! 21: .if t .sp 0.4 ! 22: .. ! 23: .Id $Id: gcc.1,v 1.4 1993/10/13 23:19:12 pesch Exp $ ! 24: .TH GCC 1 "\*(Dt" "GNU Tools" "GNU Tools" 1.1 root 25: .SH NAME 1.1.1.5 root 26: gcc, g++ \- GNU project C and C++ Compiler (v2.4) 1.1 root 27: .SH SYNOPSIS 1.1.1.6 ! root 28: .B gcc ! 29: .RI "[ " option " | " filename " ].\|.\|." 1.1 root 30: .br 1.1.1.6 ! root 31: .B g++ ! 32: .RI "[ " option " | " filename " ].\|.\|." 1.1 root 33: .SH WARNING 34: The information in this man page is an extract from the full 35: documentation of the GNU C compiler, and is limited to the meaning of 1.1.1.6 ! root 36: the options. ! 37: .PP ! 38: This man page is not kept up to date except when volunteers want to ! 39: maintain it. If you find a discrepancy between the man page and the ! 40: software, please check the Info file, which is the authoritative ! 41: documentation. ! 42: .PP ! 43: If we find that the things in this man page that are out of date cause ! 44: significant confusion or complaints, we will stop distributing the man ! 45: page. The alternative, updating the man page when we update the Info ! 46: file, is impossible because the rest of the work of maintaining GNU CC ! 47: leaves us no time for that. The GNU project regards man pages as ! 48: obsolete and should not let them take time away from other things. ! 49: .PP 1.1.1.4 root 50: For complete and current documentation, refer to the Info file `\|\c 1.1 root 51: .B gcc\c 52: \&\|' or the manual 1.1.1.6 ! root 53: .I 1.1 root 54: Using and Porting GNU CC (for version 2.0)\c 55: \&. Both are made from the Texinfo source file 56: .BR gcc.texinfo . 57: .SH DESCRIPTION 58: The C and C++ compilers are integrated. Both process input files 59: through one or more of four stages: preprocessing, compilation, 60: assembly, and linking. Source filename suffixes identify the source 61: language, but which name you use for the compiler governs default 62: assumptions: 63: .TP 64: .B gcc 65: assumes preprocessed (\c 66: .B .i\c 67: \&) files are C and assumes C style linking. 68: .TP 69: .B g++ 70: assumes preprocessed (\c 71: .B .i\c 72: \&) files are C++ and assumes C++ style linking. 1.1.1.6 ! root 73: .PP 1.1 root 74: Suffixes of source file names indicate the language and kind of 75: processing to be done: 1.1.1.6 ! root 76: .Sp ! 77: .nf ! 78: .ta \w'\fB.cxx\fP 'u ! 79: \&\fB.c\fP C source; preprocess, compile, assemble ! 80: \&\fB.C\fP C++ source; preprocess, compile, assemble ! 81: \&\fB.cc\fP C++ source; preprocess, compile, assemble ! 82: \&\fB.cxx\fP C++ source; preprocess, compile, assemble ! 83: \&\fB.m\fP Objective-C source; preprocess, compile, assemble ! 84: \&\fB.i\fP preprocessed C; compile, assemble ! 85: \&\fB.ii\fP preprocessed C++; compile, assemble ! 86: \&\fB.s\fP Assembler source; assemble ! 87: \&\fB.S\fP Assembler source; preprocess, assemble ! 88: \&\fB.h\fP Preprocessor file; not usually named on command line ! 89: .Sp ! 90: .fi ! 91: Files with other suffixes are passed to the linker. Common cases include: ! 92: .Sp ! 93: .nf ! 94: \&\fB.o\fP Object file ! 95: \&\fB.a\fP Archive file ! 96: .br ! 97: .fi ! 98: .Sp ! 99: Linking is always the last stage unless you use one of the 1.1 root 100: .BR \-c , 101: .BR \-S , 1.1.1.6 ! root 102: or ! 103: .B \-E 1.1 root 104: options to avoid it (or unless compilation errors stop the whole 1.1.1.6 ! root 105: process). For the link stage, all 1.1 root 106: .B .o 107: files corresponding to source files, 1.1.1.6 ! root 108: .B \-l ! 109: libraries, unrecognized filenames (including named 1.1 root 110: .B .o 1.1.1.6 ! root 111: object files and ! 112: .B .a 1.1 root 113: archives) 114: are passed to the linker in command-line order. 115: .SH OPTIONS 116: Options must be separate: `\|\c 117: .B \-dr\c 118: \&\|' is quite different from `\|\c 119: .B \-d \-r 1.1.1.6 ! root 120: \&\|'. ! 121: .PP 1.1 root 122: Most `\|\c 123: .B \-f\c 124: \&\|' and `\|\c 125: .B \-W\c 1.1.1.6 ! root 126: \&\|' options have two contrary forms: 1.1 root 127: .BI \-f name 128: and 129: .BI \-fno\- name\c 1.1.1.6 ! root 130: \& (or 1.1 root 131: .BI \-W name 132: and 133: .BI \-Wno\- name\c 1.1.1.6 ! root 134: \&). Only the non-default forms are shown here. ! 135: .PP 1.1 root 136: Here is a summary of all the options, grouped by type. Explanations are 137: in the following sections. 138: .hy 0 139: .na 140: .TP 141: .B Overall Options 142: .br 143: \-c 144: \-S 145: \-E 146: .RI "\-o " file 147: \-pipe 148: \-v 149: .RI "\-x " language 150: .TP 151: .B Language Options 152: \-ansi 153: \-fall\-virtual 154: \-fcond\-mismatch 155: \-fdollars\-in\-identifiers 156: \-fenum\-int\-equiv 1.1.1.6 ! root 157: \-fexternal\-templates 1.1 root 158: \-fno\-asm 159: \-fno\-builtin 160: \-fno\-strict\-prototype 161: \-fsigned\-bitfields 162: \-fsigned\-char 163: \-fthis\-is\-variable 164: \-funsigned\-bitfields 165: \-funsigned\-char 166: \-fwritable\-strings 167: \-traditional 168: \-traditional\-cpp 169: \-trigraphs 170: .TP 171: .B Warning Options 172: \-fsyntax\-only 173: \-pedantic 174: \-pedantic\-errors 175: \-w 176: \-W 177: \-Wall 178: \-Waggregate\-return 179: \-Wcast\-align 180: \-Wcast\-qual 1.1.1.5 root 181: \-Wchar\-subscript 1.1 root 182: \-Wcomment 183: \-Wconversion 184: \-Wenum\-clash 185: \-Werror 186: \-Wformat 187: .RI \-Wid\-clash\- len 188: \-Wimplicit 1.1.1.2 root 189: \-Winline 1.1 root 190: \-Wmissing\-prototypes 1.1.1.5 root 191: \-Wnested\-externs 192: \-Wno\-import 1.1.1.2 root 193: \-Wparentheses 1.1 root 194: \-Wpointer\-arith 1.1.1.5 root 195: \-Wredundant\-decls 1.1 root 196: \-Wreturn\-type 197: \-Wshadow 198: \-Wstrict\-prototypes 199: \-Wswitch 1.1.1.5 root 200: \-Wtemplate\-debugging 1.1 root 201: \-Wtraditional 202: \-Wtrigraphs 203: \-Wuninitialized 204: \-Wunused 205: \-Wwrite\-strings 206: .TP 207: .B Debugging Options 208: \-a 209: .RI \-d letters 210: \-fpretend\-float 211: \-g 1.1.1.5 root 212: .RI \-g level 213: \-gcoff 214: \-gxcoff 215: \-gxcoff+ 1.1 root 216: \-gdwarf 1.1.1.5 root 217: \-gdwarf+ 218: \-gstabs 219: \-gstabs+ 1.1 root 220: \-ggdb 221: \-p 222: \-pg 223: \-save\-temps 1.1.1.5 root 224: \-print\-libgcc\-file\-name 1.1 root 225: .TP 226: .B Optimization Options 227: \-fcaller\-saves 228: \-fcse\-follow\-jumps 1.1.1.5 root 229: \-fcse\-skip\-blocks 1.1 root 230: \-fdelayed\-branch 231: \-felide\-constructors 232: \-fexpensive\-optimizations 1.1.1.6 ! root 233: \-ffast\-math 1.1 root 234: \-ffloat\-store 235: \-fforce\-addr 236: \-fforce\-mem 237: \-finline\-functions 238: \-fkeep\-inline\-functions 239: \-fmemoize\-lookups 240: \-fno\-default\-inline 241: \-fno\-defer\-pop 242: \-fno\-function\-cse 1.1.1.5 root 243: \-fno\-inline 244: \-fno\-peephole 1.1 root 245: \-fomit\-frame\-pointer 246: \-frerun\-cse\-after\-loop 247: \-fschedule\-insns 248: \-fschedule\-insns2 249: \-fstrength\-reduce 250: \-fthread\-jumps 251: \-funroll\-all\-loops 252: \-funroll\-loops 253: \-O 254: \-O2 255: .TP 256: .B Preprocessor Options 1.1.1.5 root 257: .RI \-A assertion 1.1 root 258: \-C 259: \-dD 260: \-dM 261: \-dN 262: .RI \-D macro [\|= defn \|] 263: \-E 264: \-H 1.1.1.5 root 265: .RI "\-idirafter " dir 266: .RI "\-include " file 267: .RI "\-imacros " file 268: .RI "\-iprefix " file 269: .RI "\-iwithprefix " dir 1.1 root 270: \-M 271: \-MD 272: \-MM 273: \-MMD 274: \-nostdinc 275: \-P 276: .RI \-U macro 277: \-undef 278: .TP 1.1.1.5 root 279: .B Assembler Option 280: .RI \-Wa, option 281: .TP 1.1 root 282: .B Linker Options 283: .RI \-l library 1.1.1.5 root 284: \-nostartfiles 1.1 root 285: \-nostdlib 286: \-static 1.1.1.5 root 287: \-shared 288: \-symbolic 289: .RI "\-Xlinker\ " option 290: .RI \-Wl, option 291: .RI "\-u " symbol 1.1 root 292: .TP 293: .B Directory Options 294: .RI \-B prefix 295: .RI \-I dir 296: \-I\- 297: .RI \-L dir 298: .TP 299: .B Target Options 300: .RI "\-b " machine 301: .RI "\-V " version 302: .TP 1.1.1.5 root 303: .B Configuration Dependent Options 1.1 root 304: .I M680x0\ Options 305: .br 306: \-m68000 307: \-m68020 1.1.1.5 root 308: \-m68020\-40 309: \-m68030 310: \-m68040 1.1 root 311: \-m68881 312: \-mbitfield 313: \-mc68000 314: \-mc68020 315: \-mfpa 316: \-mnobitfield 317: \-mrtd 318: \-mshort 319: \-msoft\-float 1.1.1.6 ! root 320: .Sp 1.1 root 321: .I VAX Options 322: .br 323: \-mg 324: \-mgnu 325: \-munix 1.1.1.6 ! root 326: .Sp 1.1 root 327: .I SPARC Options 328: .br 1.1.1.5 root 329: \-mepilogue 1.1 root 330: \-mfpu 1.1.1.5 root 331: \-mhard\-float 332: \-mno\-fpu 1.1 root 333: \-mno\-epilogue 1.1.1.5 root 334: \-msoft\-float 335: \-msparclite 336: \-mv8 1.1.1.6 ! root 337: .Sp 1.1 root 338: .I Convex Options 339: .br 340: \-margcount 341: \-mc1 342: \-mc2 343: \-mnoargcount 1.1.1.6 ! root 344: .Sp 1.1 root 345: .I AMD29K Options 346: .br 347: \-m29000 348: \-m29050 349: \-mbw 350: \-mdw 351: \-mkernel\-registers 352: \-mlarge 353: \-mnbw 354: \-mnodw 355: \-msmall 356: \-mstack\-check 357: \-muser\-registers 1.1.1.6 ! root 358: .Sp 1.1 root 359: .I M88K Options 360: .br 1.1.1.5 root 361: \-m88000 362: \-m88100 363: \-m88110 1.1 root 364: \-mbig\-pic 365: \-mcheck\-zero\-division 366: \-mhandle\-large\-shift 367: \-midentify\-revision 368: \-mno\-check\-zero\-division 369: \-mno\-ocs\-debug\-info 370: \-mno\-ocs\-frame\-position 371: \-mno\-optimize\-arg\-area 1.1.1.5 root 372: \-mno\-seriazlize\-volatile 1.1 root 373: \-mno\-underscores 374: \-mocs\-debug\-info 375: \-mocs\-frame\-position 376: \-moptimize\-arg\-area 1.1.1.5 root 377: \-mserialize\-volatile 1.1 root 378: .RI \-mshort\-data\- num 379: \-msvr3 380: \-msvr4 381: \-mtrap\-large\-shift 382: \-muse\-div\-instruction 383: \-mversion\-03.00 384: \-mwarn\-passed\-structs 1.1.1.6 ! root 385: .Sp 1.1 root 386: .I RS6000 Options 387: .br 388: \-mfp\-in\-toc 389: \-mno\-fop\-in\-toc 1.1.1.6 ! root 390: .Sp 1.1 root 391: .I RT Options 392: .br 393: \-mcall\-lib\-mul 394: \-mfp\-arg\-in\-fpregs 395: \-mfp\-arg\-in\-gregs 396: \-mfull\-fp\-blocks 397: \-mhc\-struct\-return 398: \-min\-line\-mul 399: \-mminimum\-fp\-blocks 400: \-mnohc\-struct\-return 1.1.1.6 ! root 401: .Sp 1.1 root 402: .I MIPS Options 403: .br 404: \-mcpu=\fIcpu type\fP 405: \-mips2 406: \-mips3 407: \-mint64 408: \-mlong64 409: \-mlonglong128 410: \-mmips\-as 411: \-mgas 412: \-mrnames 413: \-mno\-rnames 414: \-mgpopt 415: \-mno\-gpopt 416: \-mstats 417: \-mno\-stats 418: \-mmemcpy 419: \-mno\-memcpy 420: \-mno\-mips\-tfile 421: \-mmips\-tfile 422: \-msoft\-float 423: \-mhard\-float 424: \-mabicalls 425: \-mno\-abicalls 426: \-mhalf\-pic 427: \-mno\-half\-pic 428: \-G \fInum\fP 1.1.1.5 root 429: \-nocpp 1.1.1.6 ! root 430: .Sp 1.1.1.2 root 431: .I i386 Options 432: .br 433: \-m486 1.1.1.5 root 434: \-mno\-486 435: \-msoft\-float 436: \-mno\-fp\-ret\-in\-387 1.1.1.6 ! root 437: .Sp 1.1.1.5 root 438: .I HPPA Options 439: .br 440: \-mpa\-risc\-1\-0 441: \-mpa\-risc\-1\-1 442: \-mkernel 443: \-mshared\-libs 444: \-mno\-shared\-libs 445: \-mlong\-calls 446: \-mdisable\-fpregs 447: \-mdisable\-indexing 448: \-mtrailing\-colon 1.1.1.6 ! root 449: .Sp 1.1.1.5 root 450: .I i960 Options 451: .br 452: \-m\fIcpu-type\fP 453: \-mnumerics 1.1.1.2 root 454: \-msoft\-float 1.1.1.5 root 455: \-mleaf\-procedures 456: \-mno\-leaf\-procedures 457: \-mtail\-call 458: \-mno\-tail\-call 459: \-mcomplex\-addr 460: \-mno\-complex\-addr 461: \-mcode\-align 462: \-mno\-code\-align 463: \-mic\-compat 464: \-mic2.0\-compat 465: \-mic3.0\-compat 466: \-masm\-compat 467: \-mintel\-asm 468: \-mstrict\-align 469: \-mno\-strict\-align 470: \-mold\-align 471: \-mno\-old\-align 1.1.1.6 ! root 472: .Sp 1.1.1.5 root 473: .I DEC Alpha Options 474: .br 475: \-mfp\-regs 476: \-mno\-fp\-regs 477: \-mno\-soft\-float 478: \-msoft\-float 1.1.1.6 ! root 479: .Sp 1.1.1.5 root 480: .I System V Options 481: .br 482: \-G 483: \-Qy 484: \-Qn 485: .RI \-YP, paths 486: .RI \-Ym, dir 1.1 root 487: .TP 488: .B Code Generation Options 489: .RI \-fcall\-saved\- reg 490: .RI \-fcall\-used\- reg 491: .RI \-ffixed\- reg 1.1.1.5 root 492: \-finhibit\-size\-directive 1.1 root 493: \-fnonnull\-objects 1.1.1.5 root 494: \-fno\-common 495: \-fno\-ident 496: \-fno\-gnu\-linker 1.1 root 497: \-fpcc\-struct\-return 498: \-fpic 499: \-fPIC 1.1.1.5 root 500: \-freg\-struct\-returno 1.1 root 501: \-fshared\-data 502: \-fshort\-enums 503: \-fshort\-double 504: \-fvolatile 1.1.1.5 root 505: \-fvolatile\-global 506: \-fverbose\-asm 1.1 root 507: .ad b 508: .hy 1 509: .SH OVERALL OPTIONS 510: .TP 511: .BI "\-x " "language" 1.1.1.6 ! root 512: Specify explicitly the 1.1 root 513: .I language\c 514: \& for the following input files (rather than choosing a default based 515: on the file name suffix) . This option applies to all following input 516: files until the next `\|\c 517: .B \-x\c 518: \&\|' option. Possible values of \c 519: .I language\c 520: \& are 521: `\|\c 522: .B c\c 523: \&\|', `\|\c 524: .B objective\-c\c 525: \&\|', `\|\c 526: .B c\-header\c 527: \&\|', `\|\c 528: .B c++\c 529: \&\|', 530: `\|\c 531: .B cpp\-output\c 532: \&\|', `\|\c 533: .B assembler\c 534: \&\|', and `\|\c 535: .B assembler\-with\-cpp\c 536: \&\|'. 537: .TP 538: .B \-x none 539: Turn off any specification of a language, so that subsequent files are 540: handled according to their file name suffixes (as they are if `\|\c 541: .B \-x\c 542: \&\|' 543: has not been used at all). 544: .PP 545: If you want only some of the four stages (preprocess, compile, 546: assemble, link), you can use 547: `\|\c 548: .B \-x\c 549: \&\|' (or filename suffixes) to tell \c 550: .B gcc\c 551: \& where to start, and 552: one of the options `\|\c 553: .B \-c\c 554: \&\|', `\|\c 555: .B \-S\c 556: \&\|', or `\|\c 557: .B \-E\c 558: \&\|' to say where 559: .B gcc\c 560: \& is to stop. Note that some combinations (for example, 561: `\|\c 562: .B \-x cpp\-output \-E\c 563: \&\|') instruct \c 564: .B gcc\c 565: \& to do nothing at all. 566: .TP 567: .B \-c 568: Compile or assemble the source files, but do not link. The compiler 569: output is an object file corresponding to each source file. 1.1.1.6 ! root 570: .Sp 1.1 root 571: By default, GCC makes the object file name for a source file by replacing 572: the suffix `\|\c 573: .B .c\c 574: \&\|', `\|\c 575: .B .i\c 576: \&\|', `\|\c 577: .B .s\c 578: \&\|', etc., with `\|\c 579: .B .o\c 580: \&\|'. Use 581: .B \-o\c 582: \& to select another name. 1.1.1.6 ! root 583: .Sp 1.1 root 584: GCC ignores any unrecognized input files (those that do not require 585: compilation or assembly) with the 586: .B \-c 587: option. 588: .TP 589: .B \-S 590: Stop after the stage of compilation proper; do not assemble. The output 591: is an assembler code file for each non-assembler input 592: file specified. 1.1.1.6 ! root 593: .Sp 1.1 root 594: By default, GCC makes the assembler file name for a source file by 595: replacing the suffix `\|\c 596: .B .c\c 597: \&\|', `\|\c 598: .B .i\c 599: \&\|', etc., with `\|\c 600: .B .s\c 601: \&\|'. Use 602: .B \-o\c 603: \& to select another name. 1.1.1.6 ! root 604: .Sp 1.1 root 605: GCC ignores any input files that don't require compilation. 606: .TP 607: .B \-E 608: Stop after the preprocessing stage; do not run the compiler proper. The 609: output is preprocessed source code, which is sent to the 610: standard output. 1.1.1.6 ! root 611: .Sp 1.1 root 612: GCC ignores input files which don't require preprocessing. 613: .TP 1.1.1.6 ! root 614: .BI "\-o " file 1.1 root 615: Place output in file \c 616: .I file\c 617: \&. This applies regardless to whatever 618: sort of output GCC is producing, whether it be an executable file, 619: an object file, an assembler file or preprocessed C code. 1.1.1.6 ! root 620: .Sp 1.1 root 621: Since only one output file can be specified, it does not make sense to 622: use `\|\c 623: .B \-o\c 624: \&\|' when compiling more than one input file, unless you are 625: producing an executable file as output. 1.1.1.6 ! root 626: .Sp 1.1 root 627: If you do not specify `\|\c 628: .B \-o\c 629: \&\|', the default is to put an executable file 630: in `\|\c 631: .B a.out\c 632: \&\|', the object file for `\|\c 633: .I source\c 1.1.1.6 ! root 634: .B \&.\c 1.1 root 635: .I suffix\c 636: \&\c 637: \&\|' in 638: `\|\c 639: .I source\c 1.1.1.6 ! root 640: .B \&.o\c 1.1 root 641: \&\|', its assembler file in `\|\c 642: .I source\c 1.1.1.6 ! root 643: .B \&.s\c 1.1 root 644: \&\|', and 645: all preprocessed C source on standard output. 646: .TP 647: .B \-v 648: Print (on standard error output) the commands executed to run the stages 649: of compilation. Also print the version number of the compiler driver 650: program and of the preprocessor and the compiler proper. 651: .TP 652: .B \-pipe 653: Use pipes rather than temporary files for communication between the 654: various stages of compilation. This fails to work on some systems where 655: the assembler cannot read from a pipe; but the GNU assembler has 656: no trouble. 657: .PP 658: .SH LANGUAGE OPTIONS 659: The following options control the dialect of C that the compiler 660: accepts: 661: .TP 662: .B \-ansi 1.1.1.6 ! root 663: Support all ANSI standard C programs. ! 664: .Sp 1.1 root 665: This turns off certain features of GNU C that are incompatible with 666: ANSI C, such as the \c 667: .B asm\c 668: \&, \c 669: .B inline\c 670: \& and \c 1.1.1.6 ! root 671: .B typeof 1.1 root 672: keywords, and predefined macros such as \c 673: .B unix\c 674: \& and \c 1.1.1.6 ! root 675: .B vax 1.1 root 676: that identify the type of system you are using. It also enables the 1.1.1.5 root 677: undesirable and rarely used ANSI trigraph feature, and disallows `\|\c 1.1 root 678: .B $\c 679: \&\|' as part of identifiers. 1.1.1.6 ! root 680: .Sp 1.1 root 681: The alternate keywords \c 1.1.1.6 ! root 682: .B _\|_asm_\|_\c 1.1 root 683: \&, \c 1.1.1.6 ! root 684: .B _\|_extension_\|_\c 1.1 root 685: \&, 1.1.1.6 ! root 686: .B _\|_inline_\|_\c 1.1 root 687: \& and \c 1.1.1.6 ! root 688: .B _\|_typeof_\|_\c 1.1 root 689: \& continue to work despite 690: `\|\c 691: .B \-ansi\c 692: \&\|'. You would not want to use them in an ANSI C program, of 693: course, but it is useful to put them in header files that might be included 694: in compilations done with `\|\c 695: .B \-ansi\c 696: \&\|'. Alternate predefined macros 697: such as \c 1.1.1.6 ! root 698: .B _\|_unix_\|_\c 1.1 root 699: \& and \c 1.1.1.6 ! root 700: .B _\|_vax_\|_\c 1.1 root 701: \& are also available, with or 702: without `\|\c 703: .B \-ansi\c 704: \&\|'. 1.1.1.6 ! root 705: .Sp 1.1 root 706: The `\|\c 707: .B \-ansi\c 708: \&\|' option does not cause non-ANSI programs to be 709: rejected gratuitously. For that, `\|\c 710: .B \-pedantic\c 711: \&\|' is required in 712: addition to `\|\c 713: .B \-ansi\c 1.1.1.6 ! root 714: \&\|'. ! 715: .Sp 1.1 root 716: The preprocessor predefines a macro \c 1.1.1.6 ! root 717: .B _\|_STRICT_ANSI_\|_\c 1.1 root 718: \& when you use the `\|\c 719: .B \-ansi\c 720: \&\|' 721: option. Some header files may notice this macro and refrain 722: from declaring certain functions or defining certain macros that the 723: ANSI standard doesn't call for; this is to avoid interfering with any 724: programs that might use these names for other things. 725: .TP 726: .B \-fno\-asm 727: Do not recognize \c 728: .B asm\c 729: \&, \c 730: .B inline\c 731: \& or \c 732: .B typeof\c 733: \& as a 734: keyword. These words may then be used as identifiers. You can 735: use \c 1.1.1.6 ! root 736: .B _\|_asm_\|_\c 1.1 root 737: \&, \c 1.1.1.6 ! root 738: .B _\|_inline_\|_\c 1.1 root 739: \& and \c 1.1.1.6 ! root 740: .B _\|_typeof_\|_\c 1.1 root 741: \& instead. 742: `\|\c 743: .B \-ansi\c 744: \&\|' implies `\|\c 745: .B \-fno\-asm\c 746: \&\|'. 747: .TP 748: .B \-fno\-builtin 1.1.1.5 root 749: Don't recognize built-in functions that do not begin with two leading 1.1.1.6 ! root 750: underscores. Currently, the functions affected include \c 1.1.1.5 root 751: .B _exit\c 752: \&, 753: .B abort\c 754: \&, \c 755: .B abs\c 756: \&, \c 1.1 root 757: .B alloca\c 1.1.1.5 root 758: \&, \c 759: .B cos\c 760: \&, \c 761: .B exit\c 762: \&, 763: .B fabs\c 764: \&, \c 765: .B labs\c 766: \&, \c 767: .B memcmp\c 768: \&, \c 769: .B memcpy\c 770: \&, \c 771: .B sin\c 772: \&, 773: .B sqrt\c 774: \&, \c 775: .B strcmp\c 776: \&, \c 777: .B strcpy\c 778: \&, and \c 779: .B strlen\c 1.1 root 780: \&. 1.1.1.6 ! root 781: .Sp 1.1.1.5 root 782: The `\|\c 783: .B \-ansi\c 784: \&\|' option prevents \c 785: .B alloca\c 786: \& and \c 787: .B _exit\c 788: \& from 789: being builtin functions. 1.1 root 790: .TP 791: .B \-fno\-strict\-prototype 1.1.1.5 root 792: Treat a function declaration with no arguments, such as `\|\c 793: .B int foo 794: ();\c 795: \&\|', as C would treat it\(em\&as saying nothing about the number of 796: arguments or their types (C++ only). Normally, such a declaration in 797: C++ means that the function \c 1.1 root 798: .B foo\c 1.1.1.5 root 799: \& takes no arguments. 1.1 root 800: .TP 801: .B \-trigraphs 802: Support ANSI C trigraphs. The `\|\c 803: .B \-ansi\c 804: \&\|' option implies `\|\c 805: .B \-trigraphs\c 806: \&\|'. 807: .TP 808: .B \-traditional 809: Attempt to support some aspects of traditional C compilers. 1.1.1.3 root 810: For details, see the GNU C Manual; the duplicate list here 811: has been deleted so that we won't get complaints when it 812: is out of date. 1.1.1.6 ! root 813: .Sp 1.1.1.3 root 814: But one note about C++ programs only (not C). `\|\c 1.1 root 815: .B \-traditional\c 1.1.1.6 ! root 816: \&\|' has one additional effect for C++: assignment to 1.1 root 817: .B this 818: is permitted. This is the same as the effect of `\|\c 819: .B \-fthis\-is\-variable\c 820: \&\|'. 821: .TP 822: .B \-traditional\-cpp 823: Attempt to support some aspects of traditional C preprocessors. 824: This includes the items that specifically mention the preprocessor above, 825: but none of the other effects of `\|\c 826: .B \-traditional\c 827: \&\|'. 828: .TP 829: .B \-fdollars\-in\-identifiers 830: Permit the use of `\|\c 831: .B $\c 1.1.1.5 root 832: \&\|' in identifiers (C++ only). You can also use 833: `\|\c 834: .B \-fno\-dollars\-in\-identifiers\c 835: \&\|' to explicitly prohibit use of 836: `\|\c 1.1 root 837: .B $\c 1.1.1.5 root 838: \&\|'. (GNU C++ allows `\|\c 1.1 root 839: .B $\c 1.1.1.5 root 840: \&\|' by default on some target systems 841: but not others.) 1.1 root 842: .TP 843: .B \-fenum\-int\-equiv 1.1.1.5 root 844: Permit implicit conversion of \c 1.1 root 845: .B int\c 1.1.1.5 root 846: \& to enumeration types (C++ 847: only). Normally GNU C++ allows conversion of \c 848: .B enum\c 849: \& to \c 850: .B int\c 851: \&, 852: but not the other way around. 1.1 root 853: .TP 1.1.1.6 ! root 854: .B \-fexternal\-templates ! 855: Produce smaller code for template declarations, by generating only a ! 856: single copy of each template function where it is defined (C++ only). ! 857: To use this option successfully, you must also mark all files that ! 858: use templates with either `\|\c ! 859: .B #pragma implementation\c ! 860: \&\|' (the definition) or ! 861: `\|\c ! 862: .B #pragma interface\c ! 863: \&\|' (declarations). ! 864: ! 865: When your code is compiled with `\|\c ! 866: .B \-fexternal\-templates\c ! 867: \&\|', all ! 868: template instantiations are external. You must arrange for all ! 869: necessary instantiations to appear in the implementation file; you can ! 870: do this with a \c ! 871: .B typedef\c ! 872: \& that references each instantiation needed. ! 873: Conversely, when you compile using the default option ! 874: `\|\c ! 875: .B \-fno\-external\-templates\c ! 876: \&\|', all template instantiations are ! 877: explicitly internal. ! 878: .TP 1.1 root 879: .B \-fall\-virtual 1.1.1.5 root 880: Treat all possible member functions as virtual, implicitly. All 881: member functions (except for constructor functions and 882: .B new 883: or 884: .B delete 885: member operators) are treated as virtual functions of the class where 886: they appear. 1.1.1.6 ! root 887: .Sp 1.1.1.5 root 888: This does not mean that all calls to these member functions will be 889: made through the internal table of virtual functions. Under some 890: circumstances, the compiler can determine that a call to a given 891: virtual function can be made directly; in these cases the calls are 892: direct in any case. 1.1 root 893: .TP 894: .B \-fcond\-mismatch 895: Allow conditional expressions with mismatched types in the second and 896: third arguments. The value of such an expression is void. 897: .TP 898: .B \-fthis\-is\-variable 1.1.1.5 root 899: Permit assignment to \c 1.1 root 900: .B this\c 1.1.1.5 root 901: \& (C++ only). The incorporation of 902: user-defined free store management into C++ has made assignment to 903: `\|\c 1.1 root 904: .B this\c 1.1.1.5 root 905: \&\|' an anachronism. Therefore, by default it is invalid to 906: assign to \c 1.1 root 907: .B this\c 1.1.1.5 root 908: \& within a class member function. However, for 909: backwards compatibility, you can make it valid with 910: `\|\c 911: .B \-fthis-is-variable\c 1.1 root 912: \&\|'. 913: .TP 914: .B \-funsigned\-char 915: Let the type \c 916: .B char\c 917: \& be unsigned, like \c 918: .B unsigned char\c 919: \&. 1.1.1.6 ! root 920: .Sp 1.1 root 921: Each kind of machine has a default for what \c 922: .B char\c 923: \& should 924: be. It is either like \c 925: .B unsigned char\c 926: \& by default or like 927: .B signed char\c 928: \& by default. 1.1.1.6 ! root 929: .Sp 1.1 root 930: Ideally, a portable program should always use \c 931: .B signed char\c 932: \& or 933: .B unsigned char\c 934: \& when it depends on the signedness of an object. 935: But many programs have been written to use plain \c 936: .B char\c 937: \& and 938: expect it to be signed, or expect it to be unsigned, depending on the 939: machines they were written for. This option, and its inverse, let you 940: make such a program work with the opposite default. 1.1.1.6 ! root 941: .Sp 1.1 root 942: The type \c 943: .B char\c 944: \& is always a distinct type from each of 945: .B signed char\c 946: \& and \c 947: .B unsigned char\c 948: \&, even though its behavior 949: is always just like one of those two. 950: .TP 951: .B \-fsigned\-char 952: Let the type \c 953: .B char\c 954: \& be signed, like \c 955: .B signed char\c 956: \&. 1.1.1.6 ! root 957: .Sp 1.1 root 958: Note that this is equivalent to `\|\c 959: .B \-fno\-unsigned\-char\c 960: \&\|', which is 961: the negative form of `\|\c 962: .B \-funsigned\-char\c 963: \&\|'. Likewise, 964: `\|\c 965: .B \-fno\-signed\-char\c 966: \&\|' is equivalent to `\|\c 967: .B \-funsigned\-char\c 968: \&\|'. 969: .TP 970: .B \-fsigned\-bitfields 971: .TP 972: .B \-funsigned\-bitfields 973: .TP 974: .B \-fno\-signed\-bitfields 975: .TP 976: .B \-fno\-unsigned\-bitfields 977: These options control whether a bitfield is 978: signed or unsigned, when declared with no explicit `\|\c 979: .B signed\c 980: \&\|' or `\|\c 981: .B unsigned\c 982: \&\|' qualifier. By default, such a bitfield is 983: signed, because this is consistent: the basic integer types such as 984: .B int\c 985: \& are signed types. 1.1.1.6 ! root 986: .Sp 1.1 root 987: However, when you specify `\|\c 988: .B \-traditional\c 989: \&\|', bitfields are all unsigned 990: no matter what. 991: .TP 992: .B \-fwritable\-strings 993: Store string constants in the writable data segment and don't uniquize 994: them. This is for compatibility with old programs which assume they 995: can write into string constants. `\|\c 996: .B \-traditional\c 997: \&\|' also has this 998: effect. 1.1.1.6 ! root 999: .Sp ! 1000: Writing into string constants is a very bad idea; \*(lqconstants\*(rq should 1.1 root 1001: be constant. 1002: .SH PREPROCESSOR OPTIONS 1003: These options control the C preprocessor, which is run on each C source 1004: file before actual compilation. 1.1.1.6 ! root 1005: .PP 1.1 root 1006: If you use the `\|\c 1007: .B \-E\c 1008: \&\|' option, GCC does nothing except preprocessing. 1009: Some of these options make sense only together with `\|\c 1010: .B \-E\c 1011: \&\|' because 1012: they cause the preprocessor output to be unsuitable for actual 1013: compilation. 1014: .TP 1.1.1.5 root 1015: .BI "\-include " "file" 1016: Process \c 1017: .I file\c 1018: \& as input before processing the regular input file. 1019: In effect, the contents of \c 1020: .I file\c 1021: \& are compiled first. Any `\|\c 1022: .B \-D\c 1023: \&\|' 1024: and `\|\c 1025: .B \-U\c 1026: \&\|' options on the command line are always processed before 1027: `\|\c 1028: .B \-include \c 1029: .I file\c 1030: \&\c 1031: \&\|', regardless of the order in which they are 1032: written. All the `\|\c 1033: .B \-include\c 1034: \&\|' and `\|\c 1035: .B \-imacros\c 1036: \&\|' options are 1037: processed in the order in which they are written. 1038: .TP 1039: .BI "\-imacros " file 1.1 root 1040: Process \c 1041: .I file\c 1042: \& as input, discarding the resulting output, before 1043: processing the regular input file. Because the output generated from 1044: .I file\c 1045: \& is discarded, the only effect of `\|\c 1.1.1.5 root 1046: .B \-imacros \c 1.1 root 1047: .I file\c 1048: \&\c 1049: \&\|' is to 1050: make the macros defined in \c 1051: .I file\c 1052: \& available for use in the main 1053: input. The preprocessor evaluates any `\|\c 1054: .B \-D\c 1055: \&\|' and `\|\c 1056: .B \-U\c 1057: \&\|' options 1058: on the command line before processing `\|\c 1.1.1.5 root 1059: .B \-imacros\c 1.1 root 1060: .I file\c 1.1.1.5 root 1061: \&\|', regardless of the order in 1062: which they are written. All the `\|\c 1063: .B \-include\c 1064: \&\|' and `\|\c 1065: .B \-imacros\c 1066: \&\|' 1067: options are processed in the order in which they are written. 1068: .TP 1.1.1.6 ! root 1069: .BI "\-idirafter " "dir" 1.1.1.5 root 1070: Add the directory \c 1071: .I dir\c 1072: \& to the second include path. The directories 1073: on the second include path are searched when a header file is not found 1074: in any of the directories in the main include path (the one that 1075: `\|\c 1076: .B \-I\c 1077: \&\|' adds to). 1078: .TP 1.1.1.6 ! root 1079: .BI "\-iprefix " "prefix" 1.1.1.5 root 1080: Specify \c 1081: .I prefix\c 1082: \& as the prefix for subsequent `\|\c 1083: .B \-iwithprefix\c 1084: \&\|' 1085: options. 1086: .TP 1.1.1.6 ! root 1087: .BI "\-iwithprefix " "dir" 1.1.1.5 root 1088: Add a directory to the second include path. The directory's name is 1089: made by concatenating \c 1090: .I prefix\c 1091: \& and \c 1092: .I dir\c 1093: \&, where \c 1.1.1.6 ! root 1094: .I prefix 1.1.1.5 root 1095: was specified previously with `\|\c 1096: .B \-iprefix\c 1097: \&\|'. 1.1 root 1098: .TP 1099: .B \-nostdinc 1100: Do not search the standard system directories for header files. Only 1101: the directories you have specified with `\|\c 1102: .B \-I\c 1103: \&\|' options (and the 1.1.1.6 ! root 1104: current directory, if appropriate) are searched. ! 1105: .Sp 1.1 root 1106: By using both `\|\c 1107: .B \-nostdinc\c 1108: \&\|' and `\|\c 1109: .B \-I\-\c 1110: \&\|', you can limit the include-file search file to only those 1111: directories you specify explicitly. 1112: .TP 1.1.1.5 root 1113: .B \-nostdinc++ 1.1.1.6 ! root 1114: Do not search for header files in the C++\-specific standard directories, 1.1.1.5 root 1115: but do still search the other standard directories. 1116: (This option is used when building `\|\c 1117: .B libg++\c 1118: \&\|'.) 1119: .TP 1.1 root 1120: .B \-undef 1121: Do not predefine any nonstandard macros. (Including architecture flags). 1122: .TP 1123: .B \-E 1124: Run only the C preprocessor. Preprocess all the C source files 1125: specified and output the results to standard output or to the 1126: specified output file. 1127: .TP 1128: .B \-C 1129: Tell the preprocessor not to discard comments. Used with the 1130: `\|\c 1131: .B \-E\c 1132: \&\|' option. 1133: .TP 1134: .B \-P 1135: Tell the preprocessor not to generate `\|\c 1136: .B #line\c 1137: \&\|' commands. 1138: Used with the `\|\c 1139: .B \-E\c 1140: \&\|' option. 1141: .TP 1142: .B \-M 1143: Tell the preprocessor to output a rule suitable for \c 1.1.1.6 ! root 1144: .B make 1.1 root 1145: describing the dependencies of each object file. For each source file, 1146: the preprocessor outputs one \c 1147: .B make\c 1148: \&-rule whose target is the object 1149: file name for that source file and whose dependencies are all the files 1150: `\|\c 1151: .B #include\c 1152: \&\|'d in it. This rule may be a single line or may be 1153: continued with `\|\c 1154: .B \e\c 1155: \&\|'-newline if it is long. The list of rules is 1156: printed on standard output instead of the preprocessed C program. 1.1.1.6 ! root 1157: .Sp 1.1 root 1158: `\|\c 1159: .B \-M\c 1160: \&\|' implies `\|\c 1161: .B \-E\c 1162: \&\|'. 1163: .TP 1164: .B \-MM 1165: Like `\|\c 1166: .B \-M\c 1167: \&\|' but the output mentions only the user header files 1168: included with `\|\c 1169: .B #include "\c 1170: .I file\c 1171: \&"\c 1172: \&\|'. System header files 1173: included with `\|\c 1174: .B #include <\c 1175: .I file\c 1176: \&>\c 1177: \&\|' are omitted. 1178: .TP 1179: .B \-MD 1180: Like `\|\c 1181: .B \-M\c 1182: \&\|' but the dependency information is written to files with 1183: names made by replacing `\|\c 1.1.1.5 root 1184: .B .o\c 1.1 root 1185: \&\|' with `\|\c 1186: .B .d\c 1187: \&\|' at the end of the 1.1.1.5 root 1188: output file names. This is in addition to compiling the file as 1.1 root 1189: specified\(em\&`\|\c 1190: .B \-MD\c 1191: \&\|' does not inhibit ordinary compilation the way 1192: `\|\c 1193: .B \-M\c 1194: \&\|' does. 1.1.1.6 ! root 1195: .Sp 1.1 root 1196: The Mach utility `\|\c 1197: .B md\c 1198: \&\|' can be used to merge the `\|\c 1199: .B .d\c 1200: \&\|' files 1201: into a single dependency file suitable for using with the `\|\c 1202: .B make\c 1203: \&\|' 1204: command. 1205: .TP 1206: .B \-MMD 1207: Like `\|\c 1208: .B \-MD\c 1209: \&\|' except mention only user header files, not system 1210: header files. 1211: .TP 1212: .B \-H 1213: Print the name of each header file used, in addition to other normal 1214: activities. 1215: .TP 1.1.1.6 ! root 1216: .BI "\-A" "question" ( answer ) 1.1.1.5 root 1217: Assert the answer 1218: .I answer 1219: for 1220: .I question\c 1221: \&, in case it is tested 1222: with a preprocessor conditional such as `\|\c 1223: .BI "#if #" question ( answer )\c 1224: \&\|'. `\|\c 1225: .B \-A\-\c 1226: \&\|' disables the standard 1227: assertions that normally describe the target machine. 1228: .TP 1.1.1.6 ! root 1229: .BI "\-A" "question"\c 1.1.1.5 root 1230: \&(\c 1231: .I answer\c 1232: \&) 1233: Assert the answer \c 1234: .I answer\c 1235: \& for \c 1236: .I question\c 1237: \&, in case it is tested 1238: with a preprocessor conditional such as `\|\c 1239: .B #if 1240: #\c 1241: .I question\c 1242: \&(\c 1243: .I answer\c 1244: \&)\c 1245: \&\|'. `\|\c 1246: .B \-A-\c 1247: \&\|' disables the standard 1248: assertions that normally describe the target machine. 1249: .TP 1.1 root 1250: .BI \-D macro 1251: Define macro \c 1252: .I macro\c 1253: \& with the string `\|\c 1254: .B 1\c 1255: \&\|' as its definition. 1256: .TP 1257: .BI \-D macro = defn 1258: Define macro \c 1259: .I macro\c 1260: \& as \c 1261: .I defn\c 1262: \&. All instances of `\|\c 1263: .B \-D\c 1264: \&\|' on 1265: the command line are processed before any `\|\c 1266: .B \-U\c 1267: \&\|' options. 1268: .TP 1269: .BI \-U macro 1270: Undefine macro \c 1271: .I macro\c 1272: \&. `\|\c 1273: .B \-U\c 1274: \&\|' options are evaluated after all `\|\c 1275: .B \-D\c 1276: \&\|' options, but before any `\|\c 1.1.1.5 root 1277: .B \-include\c 1278: \&\|' and `\|\c 1279: .B \-imacros\c 1.1 root 1280: \&\|' options. 1281: .TP 1282: .B \-dM 1283: Tell the preprocessor to output only a list of the macro definitions 1284: that are in effect at the end of preprocessing. Used with the `\|\c 1285: .B \-E\c 1286: \&\|' 1287: option. 1288: .TP 1289: .B \-dD 1.1.1.5 root 1290: Tell the preprocessor to pass all macro definitions into the output, in 1.1 root 1291: their proper sequence in the rest of the output. 1292: .TP 1293: .B \-dN 1294: Like `\|\c 1295: .B \-dD\c 1296: \&\|' except that the macro arguments and contents are omitted. 1297: Only `\|\c 1298: .B #define \c 1299: .I name\c 1300: \&\c 1301: \&\|' is included in the output. 1.1.1.5 root 1302: .SH ASSEMBLER OPTION 1303: .TP 1.1.1.6 ! root 1304: .BI "\-Wa," "option" 1.1.1.5 root 1305: Pass \c 1306: .I option\c 1307: \& as an option to the assembler. If \c 1.1.1.6 ! root 1308: .I option 1.1.1.5 root 1309: contains commas, it is split into multiple options at the commas. 1.1 root 1310: .SH LINKER OPTIONS 1311: These options come into play when the compiler links object files into 1312: an executable output file. They are meaningless if the compiler is 1313: not doing a link step. 1314: .TP 1315: .I object-file-name 1316: A file name that does not end in a special recognized suffix is 1317: considered to name an object file or library. (Object files are 1318: distinguished from libraries by the linker according to the file 1319: contents.) If GCC does a link step, these object files are used as input 1320: to the linker. 1321: .TP 1.1.1.6 ! root 1322: .BI \-l library 1.1 root 1323: Use the library named \c 1324: .I library\c 1325: \& when linking. 1.1.1.6 ! root 1326: .Sp 1.1 root 1327: The linker searches a standard list of directories for the library, 1328: which is actually a file named `\|\c 1329: .B lib\c 1330: .I library\c 1331: \&.a\c 1332: \&\|'. The linker 1333: then uses this file as if it had been specified precisely by name. 1.1.1.6 ! root 1334: .Sp 1.1 root 1335: The directories searched include several standard system directories 1336: plus any that you specify with `\|\c 1337: .B \-L\c 1338: \&\|'. 1.1.1.6 ! root 1339: .Sp 1.1 root 1340: Normally the files found this way are library files\(em\&archive files 1341: whose members are object files. The linker handles an archive file by 1342: scanning through it for members which define symbols that have so far 1343: been referenced but not defined. However, if the linker finds an 1344: ordinary object file rather than a library, the object file is linked 1345: in the usual fashion. The only difference between using an `\|\c 1346: .B \-l\c 1347: \&\|' option and specifying a file 1348: name is that `\|\c 1349: .B \-l\c 1.1.1.6 ! root 1350: \&\|' surrounds 1.1 root 1351: .I library 1352: with `\|\c 1353: .B lib\c 1354: \&\|' and `\|\c 1355: .B .a\c 1356: \&\|' and searches several directories. 1357: .TP 1.1.1.5 root 1358: .B \-lobjc 1359: You need this special case of the 1360: .B \-l 1361: option in order to link an Objective C program. 1362: .TP 1363: .B \-nostartfiles 1364: Do not use the standard system startup files when linking. 1365: The standard libraries are used normally. 1366: .TP 1.1 root 1367: .B \-nostdlib 1368: Don't use the standard system libraries and startup files when linking. 1369: Only the files you specify will be passed to the linker. 1370: .TP 1371: .B \-static 1372: On systems that support dynamic linking, this prevents linking with the shared 1.1.1.4 root 1373: libraries. On other systems, this option has no effect. 1.1.1.5 root 1374: .TP 1375: .B \-shared 1376: Produce a shared object which can then be linked with other objects to 1377: form an executable. Only a few systems support this option. 1378: .TP 1379: .B \-symbolic 1380: Bind references to global symbols when building a shared object. Warn 1381: about any unresolved references (unless overridden by the link editor 1382: option `\|\c 1383: .B 1384: \-Xlinker \-z \-Xlinker defs\c 1385: \&\|'). Only a few systems support 1386: this option. 1387: .TP 1.1.1.6 ! root 1388: .BI "\-Xlinker " "option" 1.1.1.5 root 1389: Pass \c 1390: .I option 1391: as an option to the linker. You can use this to 1392: supply system-specific linker options which GNU CC does not know how to 1393: recognize. 1.1.1.6 ! root 1394: .Sp 1.1.1.5 root 1395: If you want to pass an option that takes an argument, you must use 1396: `\|\c 1397: .B \-Xlinker\c 1398: \&\|' twice, once for the option and once for the argument. 1399: For example, to pass `\|\c 1400: .B 1401: \-assert definitions\c 1402: \&\|', you must write 1403: `\|\c 1404: .B 1405: \-Xlinker \-assert \-Xlinker definitions\c 1406: \&\|'. It does not work to write 1407: `\|\c 1408: .B 1.1.1.6 ! root 1409: \-Xlinker "\-assert definitions"\c 1.1.1.5 root 1410: \&\|', because this passes the entire 1411: string as a single argument, which is not what the linker expects. 1412: .TP 1.1.1.6 ! root 1413: .BI "\-Wl," "option" 1.1.1.5 root 1414: Pass \c 1415: .I option\c 1416: \& as an option to the linker. If \c 1417: .I option\c 1418: \& contains 1419: commas, it is split into multiple options at the commas. 1420: .TP 1.1.1.6 ! root 1421: .BI "\-u " "symbol" 1.1.1.5 root 1422: Pretend the symbol 1423: .I symbol 1424: is undefined, to force linking of 1425: library modules to define it. You can use `\|\c 1426: .B \-u\c 1427: \&\|' multiple times with 1428: different symbols to force loading of additional library modules. 1.1 root 1429: .SH DIRECTORY OPTIONS 1430: These options specify directories to search for header files, for 1431: libraries and for parts of the compiler: 1432: .TP 1.1.1.6 ! root 1433: .BI "\-I" "dir" 1.1 root 1434: Append directory \c 1435: .I dir\c 1436: \& to the list of directories searched for include files. 1437: .TP 1438: .B \-I\- 1439: Any directories you specify with `\|\c 1440: .B \-I\c 1441: \&\|' options before the `\|\c 1442: .B \-I\-\c 1443: \&\|' 1444: option are searched only for the case of `\|\c 1.1.1.6 ! root 1445: .B 1.1 root 1446: #include "\c 1447: .I file\c 1448: .B 1449: \&"\c 1450: \&\|'; 1451: they are not searched for `\|\c 1452: .B #include <\c 1453: .I file\c 1454: \&>\c 1455: \&\|'. 1.1.1.6 ! root 1456: .Sp 1.1 root 1457: If additional directories are specified with `\|\c 1458: .B \-I\c 1459: \&\|' options after 1460: the `\|\c 1461: .B \-I\-\c 1462: \&\|', these directories are searched for all `\|\c 1463: .B #include\c 1464: \&\|' 1465: directives. (Ordinarily \c 1466: .I all\c 1467: \& `\|\c 1468: .B \-I\c 1469: \&\|' directories are used 1470: this way.) 1.1.1.6 ! root 1471: .Sp 1.1 root 1472: In addition, the `\|\c 1473: .B \-I\-\c 1474: \&\|' option inhibits the use of the current 1475: directory (where the current input file came from) as the first search 1476: directory for `\|\c 1.1.1.6 ! root 1477: .B 1.1 root 1478: #include "\c 1479: .I file\c 1480: .B 1481: \&"\c 1482: \&\|'. There is no way to 1483: override this effect of `\|\c 1484: .B \-I\-\c 1485: \&\|'. With `\|\c 1486: .B \-I.\c 1487: \&\|' you can specify 1488: searching the directory which was current when the compiler was 1489: invoked. That is not exactly the same as what the preprocessor does 1490: by default, but it is often satisfactory. 1.1.1.6 ! root 1491: .Sp 1.1 root 1492: `\|\c 1493: .B \-I\-\c 1494: \&\|' does not inhibit the use of the standard system directories 1495: for header files. Thus, `\|\c 1496: .B \-I\-\c 1497: \&\|' and `\|\c 1498: .B \-nostdinc\c 1499: \&\|' are 1500: independent. 1501: .TP 1.1.1.6 ! root 1502: .BI "\-L" "dir" 1.1 root 1503: Add directory \c 1504: .I dir\c 1505: \& to the list of directories to be searched 1506: for `\|\c 1507: .B \-l\c 1508: \&\|'. 1509: .TP 1.1.1.6 ! root 1510: .BI "\-B" "prefix" 1.1 root 1511: This option specifies where to find the executables, libraries and 1512: data files of the compiler itself. 1.1.1.6 ! root 1513: .Sp 1.1 root 1514: The compiler driver program runs one or more of the subprograms 1515: `\|\c 1516: .B cpp\c 1517: \&\|', `\|\c 1518: .B cc1\c 1519: \&\|' (or, for C++, `\|\c 1520: .B cc1plus\c 1521: \&\|'), `\|\c 1522: .B as\c 1523: \&\|' and `\|\c 1524: .B ld\c 1525: \&\|'. It tries 1526: .I prefix\c 1527: \& as a prefix for each program it tries to run, both with and 1528: without `\|\c 1529: .I machine\c 1.1.1.6 ! root 1530: .B /\c 1.1 root 1531: .I version\c 1.1.1.6 ! root 1532: .B /\c 1.1 root 1533: \&\|'. 1.1.1.6 ! root 1534: .Sp 1.1 root 1535: For each subprogram to be run, the compiler driver first tries the 1536: `\|\c 1537: .B \-B\c 1538: \&\|' prefix, if any. If that name is not found, or if `\|\c 1539: .B \-B\c 1540: \&\|' 1541: was not specified, the driver tries two standard prefixes, which are 1542: `\|\c 1543: .B /usr/lib/gcc/\c 1544: \&\|' and `\|\c 1.1.1.2 root 1545: .B /usr/local/lib/gcc-lib/\c 1.1 root 1546: \&\|'. If neither of 1547: those results in a file name that is found, the compiler driver 1548: searches for the unmodified program 1549: name, using the directories specified in your 1550: `\|\c 1551: .B PATH\c 1552: \&\|' environment variable. 1.1.1.6 ! root 1553: .Sp 1.1 root 1554: The run-time support file `\|\c 1555: .B libgcc.a\c 1556: \&\|' is also searched for using the 1557: `\|\c 1558: .B \-B\c 1559: \&\|' prefix, if needed. If it is not found there, the two 1560: standard prefixes above are tried, and that is all. The file is left 1561: out of the link if it is not found by those means. Most of the time, 1562: on most machines, `\|\c 1563: .B libgcc.a\c 1564: \&\|' is not actually necessary. 1.1.1.6 ! root 1565: .Sp 1.1 root 1566: You can get a similar result from the environment variable 1567: .B GCC_EXEC_PREFIX\c 1568: \&; if it is defined, its value is used as a prefix 1569: in the same way. If both the `\|\c 1570: .B \-B\c 1571: \&\|' option and the 1572: .B GCC_EXEC_PREFIX\c 1573: \& variable are present, the `\|\c 1574: .B \-B\c 1575: \&\|' option is 1576: used first and the environment variable value second. 1577: .SH WARNING OPTIONS 1578: Warnings are diagnostic messages that report constructions which 1579: are not inherently erroneous but which are risky or suggest there 1580: may have been an error. 1.1.1.6 ! root 1581: .Sp 1.1 root 1582: These options control the amount and kinds of warnings produced by GNU 1583: CC: 1584: .TP 1585: .B \-fsyntax\-only 1586: Check the code for syntax errors, but don't emit any output. 1587: .TP 1588: .B \-w 1589: Inhibit all warning messages. 1590: .TP 1.1.1.5 root 1591: .B \-Wno\-import 1592: Inhibit warning messages about the use of 1593: .BR #import . 1594: .TP 1.1 root 1595: .B \-pedantic 1596: Issue all the warnings demanded by strict ANSI standard C; reject 1597: all programs that use forbidden extensions. 1.1.1.6 ! root 1598: .Sp 1.1 root 1599: Valid ANSI standard C programs should compile properly with or without 1600: this option (though a rare few will require `\|\c 1601: .B \-ansi\c 1602: \&\|'). However, 1603: without this option, certain GNU extensions and traditional C features 1604: are supported as well. With this option, they are rejected. There is 1605: no reason to \c 1606: .I use\c 1607: \& this option; it exists only to satisfy pedants. 1.1.1.6 ! root 1608: .Sp 1.1 root 1609: `\|\c 1610: .B \-pedantic\c 1611: \&\|' does not cause warning messages for use of the 1612: alternate keywords whose names begin and end with `\|\c 1.1.1.6 ! root 1613: .B _\|_\c 1.1 root 1614: \&\|'. Pedantic 1615: warnings are also disabled in the expression that follows 1.1.1.6 ! root 1616: .B _\|_extension_\|_\c 1.1 root 1617: \&. However, only system header files should use 1618: these escape routes; application programs should avoid them. 1619: .TP 1620: .B \-pedantic\-errors 1621: Like `\|\c 1622: .B \-pedantic\c 1623: \&\|', except that errors are produced rather than 1624: warnings. 1625: .TP 1626: .B \-W 1627: Print extra warning messages for these events: 1628: .TP 1629: \ \ \ \(bu 1630: A nonvolatile automatic variable might be changed by a call to 1631: .B longjmp\c 1632: \&. These warnings are possible only in 1633: optimizing compilation. 1.1.1.6 ! root 1634: .Sp 1.1 root 1635: The compiler sees only the calls to \c 1636: .B setjmp\c 1637: \&. It cannot know 1638: where \c 1639: .B longjmp\c 1640: \& will be called; in fact, a signal handler could 1641: call it at any point in the code. As a result, you may get a warning 1642: even when there is in fact no problem because \c 1643: .B longjmp\c 1644: \& cannot 1645: in fact be called at the place which would cause a problem. 1646: .TP 1647: \ \ \ \(bu 1648: A function can return either with or without a value. (Falling 1649: off the end of the function body is considered returning without 1650: a value.) For example, this function would evoke such a 1651: warning: 1.1.1.6 ! root 1652: .Sp ! 1653: .nf ! 1654: foo (a) 1.1 root 1655: { 1.1.1.6 ! root 1656: if (a > 0) ! 1657: return a; 1.1 root 1658: } 1.1.1.6 ! root 1659: .Sp ! 1660: .fi 1.1 root 1661: Spurious warnings can occur because GNU CC does not realize that 1662: certain functions (including \c 1663: .B abort\c 1664: \& and \c 1665: .B longjmp\c 1666: \&) 1667: will never return. 1668: .TP 1669: \ \ \ \(bu 1670: An expression-statement contains no side effects. 1671: .TP 1672: \ \ \ \(bu 1673: An unsigned value is compared against zero with `\|\c 1674: .B >\c 1675: \&\|' or `\|\c 1676: .B <=\c 1677: \&\|'. 1678: .PP 1679: .TP 1680: .B \-Wimplicit 1681: Warn whenever a function or parameter is implicitly declared. 1682: .TP 1683: .B \-Wreturn\-type 1684: Warn whenever a function is defined with a return-type that defaults 1685: to \c 1686: .B int\c 1687: \&. Also warn about any \c 1688: .B return\c 1689: \& statement with no 1690: return-value in a function whose return-type is not \c 1691: .B void\c 1692: \&. 1693: .TP 1694: .B \-Wunused 1695: Warn whenever a local variable is unused aside from its declaration, 1696: whenever a function is declared static but never defined, and whenever 1697: a statement computes a result that is explicitly not used. 1698: .TP 1699: .B \-Wswitch 1700: Warn whenever a \c 1701: .B switch\c 1702: \& statement has an index of enumeral type 1703: and lacks a \c 1704: .B case\c 1705: \& for one or more of the named codes of that 1706: enumeration. (The presence of a \c 1707: .B default\c 1708: \& label prevents this 1709: warning.) \c 1710: .B case\c 1711: \& labels outside the enumeration range also 1712: provoke warnings when this option is used. 1713: .TP 1714: .B \-Wcomment 1715: Warn whenever a comment-start sequence `\|\c 1.1.1.6 ! root 1716: .B /\(**\c 1.1 root 1717: \&\|' appears in a comment. 1718: .TP 1719: .B \-Wtrigraphs 1720: Warn if any trigraphs are encountered (assuming they are enabled). 1721: .TP 1722: .B \-Wformat 1723: Check calls to \c 1724: .B printf\c 1725: \& and \c 1726: .B scanf\c 1727: \&, etc., to make sure that 1728: the arguments supplied have types appropriate to the format string 1729: specified. 1730: .TP 1.1.1.5 root 1731: .B \-Wchar\-subscripts 1732: Warn if an array subscript has type 1733: .BR char . 1734: This is a common cause of error, as programmers often forget that this 1735: type is signed on some machines. 1736: .TP 1.1 root 1737: .B \-Wuninitialized 1738: An automatic variable is used without first being initialized. 1.1.1.6 ! root 1739: .Sp 1.1 root 1740: These warnings are possible only in optimizing compilation, 1741: because they require data flow information that is computed only 1742: when optimizing. If you don't specify `\|\c 1743: .B \-O\c 1744: \&\|', you simply won't 1745: get these warnings. 1.1.1.6 ! root 1746: .Sp 1.1 root 1747: These warnings occur only for variables that are candidates for 1748: register allocation. Therefore, they do not occur for a variable that 1749: is declared \c 1750: .B volatile\c 1751: \&, or whose address is taken, or whose size 1752: is other than 1, 2, 4 or 8 bytes. Also, they do not occur for 1753: structures, unions or arrays, even when they are in registers. 1.1.1.6 ! root 1754: .Sp 1.1 root 1755: Note that there may be no warning about a variable that is used only 1756: to compute a value that itself is never used, because such 1757: computations may be deleted by data flow analysis before the warnings 1758: are printed. 1.1.1.6 ! root 1759: .Sp 1.1 root 1760: These warnings are made optional because GNU CC is not smart 1761: enough to see all the reasons why the code might be correct 1762: despite appearing to have an error. Here is one example of how 1763: this can happen: 1.1.1.6 ! root 1764: .Sp ! 1765: .nf 1.1 root 1766: { 1.1.1.6 ! root 1767: int x; ! 1768: switch (y) ! 1769: { ! 1770: case 1: x = 1; ! 1771: break; ! 1772: case 2: x = 4; ! 1773: break; ! 1774: case 3: x = 5; ! 1775: } ! 1776: foo (x); 1.1 root 1777: } 1.1.1.6 ! root 1778: .Sp ! 1779: .fi 1.1 root 1780: If the value of \c 1781: .B y\c 1782: \& is always 1, 2 or 3, then \c 1783: .B x\c 1784: \& is 1785: always initialized, but GNU CC doesn't know this. Here is 1786: another common case: 1.1.1.6 ! root 1787: .Sp ! 1788: .nf 1.1 root 1789: { 1.1.1.6 ! root 1790: int save_y; ! 1791: if (change_y) save_y = y, y = new_y; ! 1792: .\|.\|. ! 1793: if (change_y) y = save_y; 1.1 root 1794: } 1.1.1.6 ! root 1795: .Sp ! 1796: .fi 1.1 root 1797: This has no bug because \c 1798: .B save_y\c 1799: \& is used only if it is set. 1.1.1.6 ! root 1800: .Sp 1.1 root 1801: Some spurious warnings can be avoided if you declare as 1802: .B volatile\c 1803: \& all the functions you use that never return. 1804: .TP 1.1.1.2 root 1805: .B \-Wparentheses 1806: Warn if parentheses are omitted in certain contexts. 1.1 root 1807: .TP 1.1.1.5 root 1808: .B \-Wtemplate\-debugging 1809: When using templates in a C++ program, warn if debugging is not yet 1810: fully available (C++ only). 1811: .TP 1.1 root 1812: .B \-Wall 1813: All of the above `\|\c 1814: .B \-W\c 1815: \&\|' options combined. These are all the 1816: options which pertain to usage that we recommend avoiding and that we 1817: believe is easy to avoid, even in conjunction with macros. 1818: .PP 1819: The remaining `\|\c 1820: .B \-W.\|.\|.\c 1821: \&\|' options are not implied by `\|\c 1822: .B \-Wall\c 1823: \&\|' 1824: because they warn about constructions that we consider reasonable to 1825: use, on occasion, in clean programs. 1826: .TP 1827: .B \-Wtraditional 1828: Warn about certain constructs that behave differently in traditional and 1829: ANSI C. 1830: .TP 1831: \ \ \ \(bu 1832: Macro arguments occurring within string constants in the macro body. 1833: These would substitute the argument in traditional C, but are part of 1834: the constant in ANSI C. 1835: .TP 1836: \ \ \ \(bu 1837: A function declared external in one block and then used after the end of 1838: the block. 1839: .TP 1840: \ \ \ \(bu 1841: A \c 1842: .B switch\c 1843: \& statement has an operand of type \c 1844: .B long\c 1845: \&. 1846: .PP 1847: .TP 1848: .B \-Wshadow 1849: Warn whenever a local variable shadows another local variable. 1850: .TP 1.1.1.6 ! root 1851: .BI "\-Wid\-clash\-" "len" 1.1 root 1852: Warn whenever two distinct identifiers match in the first \c 1.1.1.6 ! root 1853: .I len 1.1 root 1854: characters. This may help you prepare a program that will compile 1855: with certain obsolete, brain-damaged compilers. 1856: .TP 1857: .B \-Wpointer\-arith 1.1.1.6 ! root 1858: Warn about anything that depends on the \*(lqsize of\*(rq a function type or 1.1 root 1859: of \c 1860: .B void\c 1861: \&. GNU C assigns these types a size of 1, for 1862: convenience in calculations with \c 1.1.1.6 ! root 1863: .B void \(**\c 1.1 root 1864: \& pointers and pointers 1865: to functions. 1866: .TP 1867: .B \-Wcast\-qual 1868: Warn whenever a pointer is cast so as to remove a type qualifier from 1869: the target type. For example, warn if a \c 1.1.1.6 ! root 1870: .B const char \(**\c 1.1 root 1871: \& is cast 1872: to an ordinary \c 1.1.1.6 ! root 1873: .B char \(**\c 1.1 root 1874: \&. 1875: .TP 1876: .B \-Wcast\-align 1877: Warn whenever a pointer is cast such that the required alignment of the 1878: target is increased. For example, warn if a \c 1.1.1.6 ! root 1879: .B char \(**\c 1.1 root 1880: \& is cast to 1881: an \c 1.1.1.6 ! root 1882: .B int \(**\c 1.1 root 1883: \& on machines where integers can only be accessed at 1884: two- or four-byte boundaries. 1885: .TP 1886: .B \-Wwrite\-strings 1887: Give string constants the type \c 1888: .B const char[\c 1889: .I length\c 1.1.1.6 ! root 1890: .B ]\c 1.1 root 1891: \& so that 1892: copying the address of one into a non-\c 1893: .B const\c 1894: \& \c 1.1.1.6 ! root 1895: .B char \(** 1.1 root 1896: pointer will get a warning. These warnings will help you find at 1897: compile time code that can try to write into a string constant, but 1898: only if you have been very careful about using \c 1899: .B const\c 1900: \& in 1901: declarations and prototypes. Otherwise, it will just be a nuisance; 1902: this is why we did not make `\|\c 1903: .B \-Wall\c 1904: \&\|' request these warnings. 1905: .TP 1906: .B \-Wconversion 1907: Warn if a prototype causes a type conversion that is different from what 1908: would happen to the same argument in the absence of a prototype. This 1909: includes conversions of fixed point to floating and vice versa, and 1910: conversions changing the width or signedness of a fixed point argument 1911: except when the same as the default promotion. 1912: .TP 1.1.1.2 root 1913: .B \-Waggregate\-return 1914: Warn if any functions that return structures or unions are defined or 1915: called. (In languages where you can return an array, this also elicits 1916: a warning.) 1917: .TP 1918: .B \-Wstrict\-prototypes 1919: Warn if a function is declared or defined without specifying the 1920: argument types. (An old-style function definition is permitted without 1921: a warning if preceded by a declaration which specifies the argument 1922: types.) 1923: .TP 1924: .B \-Wmissing\-prototypes 1925: Warn if a global function is defined without a previous prototype 1926: declaration. This warning is issued even if the definition itself 1927: provides a prototype. The aim is to detect global functions that fail 1928: to be declared in header files. 1929: .TP 1.1.1.5 root 1930: .B \-Wredundant-decls 1931: Warn if anything is declared more than once in the same scope, even in 1932: cases where multiple declaration is valid and changes nothing. 1933: .TP 1934: .B \-Wnested-externs 1935: Warn if an \c 1936: .B extern\c 1937: \& declaration is encountered within an function. 1938: .TP 1.1 root 1939: .B \-Wenum\-clash 1.1.1.5 root 1940: Warn about conversion between different enumeration types (C++ only). 1.1 root 1941: .TP 1942: .B \-Woverloaded\-virtual 1.1.1.5 root 1943: (C++ only.) 1.1 root 1944: In a derived class, the definitions of virtual functions must match 1945: the type signature of a virtual function declared in the base class. 1946: Use this option to request warnings when a derived class declares a 1947: function that may be an erroneous attempt to define a virtual 1948: function: that is, warn when a function with the same name as a 1949: virtual function in the base class, but with a type signature that 1950: doesn't match any virtual functions from the base class. 1.1.1.2 root 1951: .TP 1952: .B \-Winline 1953: Warn if a function can not be inlined, and either it was declared as inline, 1954: or else the 1955: .B \-finline\-functions 1956: option was given. 1957: .TP 1958: .B \-Werror 1959: Treat warnings as errors; abort compilation after any warning. 1.1 root 1960: .SH DEBUGGING OPTIONS 1961: GNU CC has various special options that are used for debugging 1962: either your program or GCC: 1963: .TP 1964: .B \-g 1965: Produce debugging information in the operating system's native format 1.1.1.5 root 1966: (stabs, COFF, XCOFF, or DWARF). GDB can work with this debugging 1967: information. 1.1.1.6 ! root 1968: .Sp 1.1.1.5 root 1969: On most systems that use stabs format, `\|\c 1.1 root 1970: .B \-g\c 1.1.1.5 root 1971: \&\|' enables use of extra 1972: debugging information that only GDB can use; this extra information 1973: makes debugging work better in GDB but will probably make other debuggers 1974: crash or 1975: refuse to read the program. If you want to control for certain whether 1976: to generate the extra information, use `\|\c 1977: .B \-gstabs+\c 1978: \&\|', `\|\c 1979: .B \-gstabs\c 1980: \&\|', 1.1 root 1981: `\|\c 1.1.1.5 root 1982: .B \-gxcoff+\c 1983: \&\|', `\|\c 1984: .B \-gxcoff\c 1985: \&\|', `\|\c 1986: .B \-gdwarf+\c 1987: \&\|', or `\|\c 1988: .B \-gdwarf\c 1989: \&\|' 1990: (see below). 1.1.1.6 ! root 1991: .Sp 1.1 root 1992: Unlike most other C compilers, GNU CC allows you to use `\|\c 1993: .B \-g\c 1994: \&\|' with 1995: `\|\c 1996: .B \-O\c 1997: \&\|'. The shortcuts taken by optimized code may occasionally 1998: produce surprising results: some variables you declared may not exist 1999: at all; flow of control may briefly move where you did not expect it; 2000: some statements may not be executed because they compute constant 2001: results or their values were already at hand; some statements may 2002: execute in different places because they were moved out of loops. 1.1.1.6 ! root 2003: .Sp 1.1 root 2004: Nevertheless it proves possible to debug optimized output. This makes 2005: it reasonable to use the optimizer for programs that might have bugs. 1.1.1.6 ! root 2006: .PP 1.1.1.5 root 2007: The following options are useful when GNU CC is generated with the 2008: capability for more than one debugging format. 1.1 root 2009: .TP 2010: .B \-ggdb 1.1.1.5 root 2011: Produce debugging information in the native format (if that is supported), 2012: including GDB extensions if at all possible. 1.1 root 2013: .TP 1.1.1.5 root 2014: .B \-gstabs 2015: Produce debugging information in stabs format (if that is supported), 2016: without GDB extensions. This is the format used by DBX on most BSD 2017: systems. 1.1 root 2018: .TP 1.1.1.5 root 2019: .B \-gstabs+ 2020: Produce debugging information in stabs format (if that is supported), 2021: using GNU extensions understood only by the GNU debugger (GDB). The 2022: use of these extensions is likely to make other debuggers crash or 2023: refuse to read the program. 2024: .TP 2025: .B \-gcoff 2026: Produce debugging information in COFF format (if that is supported). 2027: This is the format used by SDB on most System V systems prior to 2028: System V Release 4. 2029: .TP 2030: .B \-gxcoff 2031: Produce debugging information in XCOFF format (if that is supported). 2032: This is the format used by the DBX debugger on IBM RS/6000 systems. 2033: .TP 2034: .B \-gxcoff+ 2035: Produce debugging information in XCOFF format (if that is supported), 2036: using GNU extensions understood only by the GNU debugger (GDB). The 2037: use of these extensions is likely to make other debuggers crash or 2038: refuse to read the program. 1.1 root 2039: .TP 2040: .B \-gdwarf 2041: Produce debugging information in DWARF format (if that is supported). 1.1.1.5 root 2042: This is the format used by SDB on most System V Release 4 systems. 2043: .TP 2044: .B \-gdwarf+ 2045: Produce debugging information in DWARF format (if that is supported), 2046: using GNU extensions understood only by the GNU debugger (GDB). The 2047: use of these extensions is likely to make other debuggers crash or 2048: refuse to read the program. 1.1 root 2049: .PP 2050: .BI "\-g" "level" 2051: .br 2052: .BI "\-ggdb" "level" 2053: .br 1.1.1.5 root 2054: .BI "\-gstabs" "level" 1.1 root 2055: .br 1.1.1.5 root 2056: .BI "\-gcoff" "level" 2057: .BI "\-gxcoff" "level" 1.1 root 2058: .TP 2059: .BI "\-gdwarf" "level" 2060: Request debugging information and also use \c 2061: .I level\c 2062: \& to specify how 2063: much information. The default level is 2. 1.1.1.6 ! root 2064: .Sp 1.1 root 2065: Level 1 produces minimal information, enough for making backtraces in 2066: parts of the program that you don't plan to debug. This includes 2067: descriptions of functions and external variables, but no information 2068: about local variables and no line numbers. 1.1.1.6 ! root 2069: .Sp 1.1.1.5 root 2070: Level 3 includes extra information, such as all the macro definitions 2071: present in the program. Some debuggers support macro expansion when 2072: you use `\|\c 2073: .B \-g3\c 2074: \&\|'. 1.1 root 2075: .TP 2076: .B \-p 2077: Generate extra code to write profile information suitable for the 2078: analysis program \c 2079: .B prof\c 2080: \&. 2081: .TP 2082: .B \-pg 2083: Generate extra code to write profile information suitable for the 2084: analysis program \c 2085: .B gprof\c 2086: \&. 2087: .TP 2088: .B \-a 2089: Generate extra code to write profile information for basic blocks, 2090: which will record the number of times each basic block is executed. 2091: This data could be analyzed by a program like \c 2092: .B tcov\c 2093: \&. Note, 2094: however, that the format of the data is not what \c 2095: .B tcov\c 2096: \& expects. 2097: Eventually GNU \c 2098: .B gprof\c 2099: \& should be extended to process this data. 2100: .TP 1.1.1.6 ! root 2101: .BI "\-d" "letters" 1.1 root 2102: Says to make debugging dumps during compilation at times specified by 2103: .I letters\c 2104: \&. This is used for debugging the compiler. The file names 2105: for most of the dumps are made by appending a word to the source file 2106: name (e.g. `\|\c 2107: .B foo.c.rtl\c 2108: \&\|' or `\|\c 2109: .B foo.c.jump\c 2110: \&\|'). 2111: .TP 2112: .B \-dM 2113: Dump all macro definitions, at the end of preprocessing, and write no 2114: output. 2115: .TP 2116: .B \-dN 2117: Dump all macro names, at the end of preprocessing. 2118: .TP 2119: .B \-dD 2120: Dump all macro definitions, at the end of preprocessing, in addition to 2121: normal output. 2122: .TP 2123: .B \-dy 2124: Dump debugging information during parsing, to standard error. 2125: .TP 2126: .B \-dr 2127: Dump after RTL generation, to `\|\c 2128: .I file\c 1.1.1.6 ! root 2129: .B \&.rtl\c 1.1 root 2130: \&\|'. 2131: .TP 2132: .B \-dx 2133: Just generate RTL for a function instead of compiling it. Usually used 2134: with `\|\c 2135: .B r\c 2136: \&\|'. 2137: .TP 2138: .B \-dj 2139: Dump after first jump optimization, to `\|\c 2140: .I file\c 1.1.1.6 ! root 2141: .B \&.jump\c 1.1 root 2142: \&\|'. 2143: .TP 2144: .B \-ds 2145: Dump after CSE (including the jump optimization that sometimes 2146: follows CSE), to `\|\c 2147: .I file\c 1.1.1.6 ! root 2148: .B \&.cse\c 1.1 root 2149: \&\|'. 2150: .TP 2151: .B \-dL 2152: Dump after loop optimization, to `\|\c 2153: .I file\c 1.1.1.6 ! root 2154: .B \&.loop\c 1.1 root 2155: \&\|'. 2156: .TP 2157: .B \-dt 2158: Dump after the second CSE pass (including the jump optimization that 2159: sometimes follows CSE), to `\|\c 2160: .I file\c 1.1.1.6 ! root 2161: .B \&.cse2\c 1.1 root 2162: \&\|'. 2163: .TP 2164: .B \-df 2165: Dump after flow analysis, to `\|\c 2166: .I file\c 1.1.1.6 ! root 2167: .B \&.flow\c 1.1 root 2168: \&\|'. 2169: .TP 2170: .B \-dc 2171: Dump after instruction combination, to `\|\c 2172: .I file\c 1.1.1.6 ! root 2173: .B \&.combine\c 1.1 root 2174: \&\|'. 2175: .TP 2176: .B \-dS 2177: Dump after the first instruction scheduling pass, to 2178: `\|\c 2179: .I file\c 1.1.1.6 ! root 2180: .B \&.sched\c 1.1 root 2181: \&\|'. 2182: .TP 2183: .B \-dl 2184: Dump after local register allocation, to `\|\c 2185: .I file\c 1.1.1.6 ! root 2186: .B \&.lreg\c 1.1 root 2187: \&\|'. 2188: .TP 2189: .B \-dg 2190: Dump after global register allocation, to `\|\c 2191: .I file\c 1.1.1.6 ! root 2192: .B \&.greg\c 1.1 root 2193: \&\|'. 2194: .TP 2195: .B \-dR 2196: Dump after the second instruction scheduling pass, to 2197: `\|\c 2198: .I file\c 1.1.1.6 ! root 2199: .B \&.sched2\c 1.1 root 2200: \&\|'. 2201: .TP 2202: .B \-dJ 2203: Dump after last jump optimization, to `\|\c 2204: .I file\c 1.1.1.6 ! root 2205: .B \&.jump2\c 1.1 root 2206: \&\|'. 2207: .TP 2208: .B \-dd 2209: Dump after delayed branch scheduling, to `\|\c 2210: .I file\c 1.1.1.6 ! root 2211: .B \&.dbr\c 1.1 root 2212: \&\|'. 2213: .TP 2214: .B \-dk 2215: Dump after conversion from registers to stack, to `\|\c 2216: .I file\c 1.1.1.6 ! root 2217: .B \&.stack\c 1.1 root 2218: \&\|'. 2219: .TP 1.1.1.5 root 2220: .B \-da 2221: Produce all the dumps listed above. 2222: .TP 1.1 root 2223: .B \-dm 2224: Print statistics on memory usage, at the end of the run, to 2225: standard error. 2226: .TP 2227: .B \-dp 2228: Annotate the assembler output with a comment indicating which 2229: pattern and alternative was used. 2230: .TP 2231: .B \-fpretend\-float 2232: When running a cross-compiler, pretend that the target machine uses the 2233: same floating point format as the host machine. This causes incorrect 2234: output of the actual floating constants, but the actual instruction 2235: sequence will probably be the same as GNU CC would make when running on 2236: the target machine. 2237: .TP 2238: .B \-save\-temps 1.1.1.6 ! root 2239: Store the usual \*(lqtemporary\*(rq intermediate files permanently; place them 1.1 root 2240: in the current directory and name them based on the source file. Thus, 2241: compiling `\|\c 2242: .B foo.c\c 2243: \&\|' with `\|\c 2244: .B \-c \-save\-temps\c 2245: \&\|' would produce files 2246: `\|\c 2247: .B foo.cpp\c 2248: \&\|' and `\|\c 2249: .B foo.s\c 2250: \&\|', as well as `\|\c 2251: .B foo.o\c 2252: \&\|'. 1.1.1.5 root 2253: .TP 2254: .B \-print\-libgcc\-file\-name 2255: Print the full absolute name of the library file `\|\c 2256: .B libgcc.a\c 2257: \&\|' that 2258: would be used when linking\(em\&and do not do anything else. With this 2259: option, GNU CC does not compile or link anything; it just prints the 2260: file name. 1.1 root 2261: .SH OPTIMIZATION OPTIONS 2262: These options control various sorts of optimizations: 1.1.1.6 ! root 2263: .TP 1.1 root 2264: .B \-O 1.1.1.5 root 2265: .TP 2266: .B \-O1 1.1 root 2267: Optimize. Optimizing compilation takes somewhat more time, and a lot 2268: more memory for a large function. 1.1.1.6 ! root 2269: .Sp 1.1 root 2270: Without `\|\c 2271: .B \-O\c 2272: \&\|', the compiler's goal is to reduce the cost of 2273: compilation and to make debugging produce the expected results. 2274: Statements are independent: if you stop the program with a breakpoint 2275: between statements, you can then assign a new value to any variable or 2276: change the program counter to any other statement in the function and 2277: get exactly the results you would expect from the source code. 1.1.1.6 ! root 2278: .Sp 1.1 root 2279: Without `\|\c 2280: .B \-O\c 2281: \&\|', only variables declared \c 2282: .B register\c 2283: \& are 2284: allocated in registers. The resulting compiled code is a little worse 2285: than produced by PCC without `\|\c 2286: .B \-O\c 2287: \&\|'. 1.1.1.6 ! root 2288: .Sp 1.1 root 2289: With `\|\c 2290: .B \-O\c 2291: \&\|', the compiler tries to reduce code size and execution 2292: time. 1.1.1.6 ! root 2293: .Sp 1.1 root 2294: When you specify `\|\c 2295: .B \-O\c 2296: \&\|', `\|\c 2297: .B \-fthread\-jumps\c 2298: \&\|' and 2299: `\|\c 2300: .B \-fdelayed\-branch\c 2301: \&\|' are turned on. On some machines other 2302: flags may also be turned on. 2303: .TP 2304: .B \-O2 1.1.1.5 root 2305: Optimize even more. Nearly all supported optimizations that do not 2306: involve a space-speed tradeoff are performed. As compared to 1.1 root 2307: .B \-O\c 1.1.1.5 root 2308: \&, 2309: this option increases both compilation time and the performance of the 1.1 root 2310: generated code. 1.1.1.6 ! root 2311: .Sp 1.1.1.5 root 2312: .B \-O2 2313: turns on all 2314: .BI \-f flag 2315: options that enable more optimization, except for 1.1 root 2316: .B \-funroll\-loops\c 1.1.1.5 root 2317: \&, 2318: .B \-funroll\-all\-loops 2319: and 2320: .BR \-fomit\-frame\-pointer . 2321: .TP 2322: .B \-O0 2323: Do not optimize. 1.1.1.6 ! root 2324: .Sp 1.1.1.5 root 2325: If you use multiple 2326: .B \-O 2327: options, with or without level numbers, the last such option is the 2328: one that is effective. 1.1 root 2329: .PP 2330: Options of the form `\|\c 2331: .B \-f\c 2332: .I flag\c 2333: \&\c 2334: \&\|' specify machine-independent 2335: flags. Most flags have both positive and negative forms; the negative 2336: form of `\|\c 2337: .B \-ffoo\c 2338: \&\|' would be `\|\c 2339: .B \-fno\-foo\c 2340: \&\|'. The following list shows 2341: only one form\(em\&the one which is not the default. 2342: You can figure out the other form by either removing `\|\c 2343: .B no\-\c 2344: \&\|' or 2345: adding it. 2346: .TP 2347: .B \-ffloat\-store 2348: Do not store floating point variables in registers. This 2349: prevents undesirable excess precision on machines such as the 2350: 68000 where the floating registers (of the 68881) keep more 2351: precision than a \c 2352: .B double\c 2353: \& is supposed to have. 1.1.1.6 ! root 2354: .Sp 1.1 root 2355: For most programs, the excess precision does only good, but a few 2356: programs rely on the precise definition of IEEE floating point. 2357: Use `\|\c 2358: .B \-ffloat\-store\c 2359: \&\|' for such programs. 2360: .TP 2361: .B \-fmemoize\-lookups 2362: .TP 2363: .B \-fsave\-memoized 1.1.1.5 root 2364: Use heuristics to compile faster (C++ only). These heuristics are not 2365: enabled by default, since they are only effective for certain input 2366: files. Other input files compile more slowly. 1.1.1.6 ! root 2367: .Sp 1.1 root 2368: The first time the compiler must build a call to a member function (or 2369: reference to a data member), it must (1) determine whether the class 2370: implements member functions of that name; (2) resolve which member 2371: function to call (which involves figuring out what sorts of type 2372: conversions need to be made); and (3) check the visibility of the member 2373: function to the caller. All of this adds up to slower compilation. 2374: Normally, the second time a call is made to that member function (or 2375: reference to that data member), it must go through the same lengthy 2376: process again. This means that code like this 1.1.1.6 ! root 2377: .Sp ! 2378: \& cout << "This " << p << " has " << n << " legs.\en"; ! 2379: .Sp 1.1 root 2380: makes six passes through all three steps. By using a software cache, 1.1.1.6 ! root 2381: a \*(lqhit\*(rq significantly reduces this cost. Unfortunately, using the 1.1 root 2382: cache introduces another layer of mechanisms which must be implemented, 2383: and so incurs its own overhead. `\|\c 2384: .B \-fmemoize\-lookups\c 2385: \&\|' enables 2386: the software cache. 1.1.1.6 ! root 2387: .Sp 1.1 root 2388: Because access privileges (visibility) to members and member functions 1.1.1.6 ! root 2389: may differ from one function context to the next, 1.1 root 2390: .B g++ 1.1.1.5 root 2391: may need to flush the cache. With the `\|\c 1.1 root 2392: .B \-fmemoize\-lookups\c 2393: \&\|' flag, the cache is flushed after every 2394: function that is compiled. The `\|\c 2395: \-fsave\-memoized\c 2396: \&\|' flag enables the same software cache, but when the compiler 2397: determines that the context of the last function compiled would yield 2398: the same access privileges of the next function to compile, it 1.1.1.6 ! root 2399: preserves the cache. 1.1 root 2400: This is most helpful when defining many member functions for the same 2401: class: with the exception of member functions which are friends of 2402: other classes, each member function has exactly the same access 2403: privileges as every other, and the cache need not be flushed. 2404: .TP 2405: .B \-fno\-default\-inline 1.1.1.5 root 2406: Don't make member functions inline by default merely because they are 2407: defined inside the class scope (C++ only). 1.1 root 2408: .TP 2409: .B \-fno\-defer\-pop 2410: Always pop the arguments to each function call as soon as that 2411: function returns. For machines which must pop arguments after a 2412: function call, the compiler normally lets arguments accumulate on the 2413: stack for several function calls and pops them all at once. 2414: .TP 2415: .B \-fforce\-mem 2416: Force memory operands to be copied into registers before doing 2417: arithmetic on them. This may produce better code by making all 2418: memory references potential common subexpressions. When they are 2419: not common subexpressions, instruction combination should 2420: eliminate the separate register-load. I am interested in hearing 2421: about the difference this makes. 2422: .TP 2423: .B \-fforce\-addr 2424: Force memory address constants to be copied into registers before 2425: doing arithmetic on them. This may produce better code just as 2426: `\|\c 2427: .B \-fforce\-mem\c 2428: \&\|' may. I am interested in hearing about the 2429: difference this makes. 2430: .TP 2431: .B \-fomit\-frame\-pointer 2432: Don't keep the frame pointer in a register for functions that 2433: don't need one. This avoids the instructions to save, set up and 2434: restore frame pointers; it also makes an extra register available 2435: in many functions. \c 2436: .I It also makes debugging impossible on 1.1.1.6 ! root 2437: most machines. ! 2438: .Sp 1.1 root 2439: On some machines, such as the Vax, this flag has no effect, because 2440: the standard calling sequence automatically handles the frame pointer 2441: and nothing is saved by pretending it doesn't exist. The 2442: machine-description macro \c 2443: .B FRAME_POINTER_REQUIRED\c 2444: \& controls 1.1.1.6 ! root 2445: whether a target machine supports this flag. 1.1 root 2446: .TP 2447: .B \-finline\-functions 2448: Integrate all simple functions into their callers. The compiler 2449: heuristically decides which functions are simple enough to be worth 2450: integrating in this way. 1.1.1.6 ! root 2451: .Sp 1.1 root 2452: If all calls to a given function are integrated, and the function is 2453: declared \c 2454: .B static\c 2455: \&, then GCC normally does not output the function as 2456: assembler code in its own right. 2457: .TP 2458: .B \-fcaller\-saves 2459: Enable values to be allocated in registers that will be clobbered by 2460: function calls, by emitting extra instructions to save and restore the 2461: registers around such calls. Such allocation is done only when it 2462: seems to result in better code than would otherwise be produced. 1.1.1.6 ! root 2463: .Sp 1.1 root 2464: This option is enabled by default on certain machines, usually those 2465: which have no call-preserved registers to use instead. 2466: .TP 2467: .B \-fkeep\-inline\-functions 2468: Even if all calls to a given function are integrated, and the function 2469: is declared \c 2470: .B static\c 2471: \&, nevertheless output a separate run-time 2472: callable version of the function. 2473: .TP 2474: .B \-fno\-function\-cse 2475: Do not put function addresses in registers; make each instruction that 2476: calls a constant function contain the function's address explicitly. 1.1.1.6 ! root 2477: .Sp 1.1 root 2478: This option results in less efficient code, but some strange hacks 2479: that alter the assembler output may be confused by the optimizations 2480: performed when this option is not used. 1.1.1.5 root 2481: .TP 2482: .B \-fno\-peephole 2483: Disable any machine-specific peephole optimizations. 2484: .TP 2485: .B \-ffast-math 2486: This option allows GCC to violate some ANSI or IEEE rules/specifications 2487: in the interest of optimizing code for speed. For example, it allows 2488: the compiler to assume arguments to the \c 2489: .B sqrt\c 1.1.1.6 ! root 2490: \& function are ! 2491: non-negative numbers. ! 2492: .Sp 1.1.1.5 root 2493: This option should never be turned on by any `\|\c 2494: .B \-O\c 1.1.1.6 ! root 2495: \&\|' option since ! 2496: it can result in incorrect output for programs which depend on 1.1.1.5 root 2497: an exact implementation of IEEE or ANSI rules/specifications for 2498: math functions. 1.1 root 2499: .PP 2500: The following options control specific optimizations. The `\|\c 2501: .B \-O2\c 2502: \&\|' 2503: option turns on all of these optimizations except `\|\c 2504: .B \-funroll\-loops\c 2505: \&\|' 2506: and `\|\c 2507: .B \-funroll\-all\-loops\c 1.1.1.6 ! root 2508: \&\|'. ! 2509: .PP 1.1 root 2510: The `\|\c 2511: .B \-O\c 2512: \&\|' option usually turns on 2513: the `\|\c 2514: .B \-fthread\-jumps\c 2515: \&\|' and `\|\c 2516: .B \-fdelayed\-branch\c 2517: \&\|' options, but 2518: specific machines may change the default optimizations. 1.1.1.6 ! root 2519: .PP ! 2520: You can use the following flags in the rare cases when \*(lqfine-tuning\*(rq 1.1 root 2521: of optimizations to be performed is desired. 2522: .TP 2523: .B \-fstrength\-reduce 2524: Perform the optimizations of loop strength reduction and 2525: elimination of iteration variables. 2526: .TP 2527: .B \-fthread\-jumps 2528: Perform optimizations where we check to see if a jump branches to a 2529: location where another comparison subsumed by the first is found. If 2530: so, the first branch is redirected to either the destination of the 2531: second branch or a point immediately following it, depending on whether 2532: the condition is known to be true or false. 2533: .TP 2534: .B \-funroll\-loops 2535: Perform the optimization of loop unrolling. This is only done for loops 2536: whose number of iterations can be determined at compile time or run time. 2537: .TP 2538: .B \-funroll\-all\-loops 2539: Perform the optimization of loop unrolling. This is done for all loops. 2540: This usually makes programs run more slowly. 2541: .TP 2542: .B \-fcse\-follow\-jumps 1.1.1.5 root 2543: In common subexpression elimination, scan through jump instructions 2544: when the target of the jump is not reached by any other path. For 2545: example, when CSE encounters an \c 2546: .B if\c 2547: \& statement with an 2548: .B else\c 2549: \& clause, CSE will follow the jump when the condition 2550: tested is false. 2551: .TP 2552: .B \-fcse\-skip\-blocks 2553: This is similar to `\|\c 2554: .B \-fcse\-follow\-jumps\c 2555: \&\|', but causes CSE to 2556: follow jumps which conditionally skip over blocks. When CSE 2557: encounters a simple \c 2558: .B if\c 2559: \& statement with no else clause, 2560: `\|\c 2561: .B \-fcse\-skip\-blocks\c 2562: \&\|' causes CSE to follow the jump around the 2563: body of the \c 2564: .B if\c 2565: \&. 1.1 root 2566: .TP 2567: .B \-frerun\-cse\-after\-loop 2568: Re-run common subexpression elimination after loop optimizations has been 1.1.1.6 ! root 2569: performed. 1.1 root 2570: .TP 2571: .B \-felide\-constructors 1.1.1.5 root 2572: Elide constructors when this seems plausible (C++ only). With this 2573: flag, GNU C++ initializes \c 2574: .B y\c 2575: \& directly from the call to \c 1.1.1.6 ! root 2576: .B foo 1.1.1.5 root 2577: without going through a temporary in the following code: 1.1.1.6 ! root 2578: .Sp ! 2579: A foo (); ! 2580: A y = foo (); ! 2581: .Sp 1.1.1.5 root 2582: Without this option, GNU C++ first initializes \c 1.1 root 2583: .B y\c 1.1.1.5 root 2584: \& by calling the 2585: appropriate constructor for type \c 2586: .B A\c 2587: \&; then assigns the result of 2588: .B foo\c 2589: \& to a temporary; and, finally, replaces the initial valyue of 2590: `\|\c 2591: .B y\c 2592: \&\|' with the temporary. 1.1.1.6 ! root 2593: .Sp 1.1.1.5 root 2594: The default behavior (`\|\c 2595: .B \-fno\-elide\-constructors\c 2596: \&\|') is specified by 2597: the draft ANSI C++ standard. If your program's constructors have side 2598: effects, using `\|\c 2599: .B \-felide-constructors\c 2600: \&\|' can make your program act 2601: differently, since some constructor calls may be omitted. 1.1 root 2602: .TP 2603: .B \-fexpensive\-optimizations 2604: Perform a number of minor optimizations that are relatively expensive. 2605: .TP 2606: .B \-fdelayed\-branch 2607: If supported for the target machine, attempt to reorder instructions 2608: to exploit instruction slots available after delayed branch 2609: instructions. 2610: .TP 2611: .B \-fschedule\-insns 2612: If supported for the target machine, attempt to reorder instructions to 2613: eliminate execution stalls due to required data being unavailable. This 2614: helps machines that have slow floating point or memory load instructions 2615: by allowing other instructions to be issued until the result of the load 2616: or floating point instruction is required. 2617: .TP 2618: .B \-fschedule\-insns2 2619: Similar to `\|\c 2620: .B \-fschedule\-insns\c 2621: \&\|', but requests an additional pass of 2622: instruction scheduling after register allocation has been done. This is 2623: especially useful on machines with a relatively small number of 2624: registers and where memory load instructions take more than one cycle. 2625: .SH TARGET OPTIONS 2626: By default, GNU CC compiles code for the same type of machine that you 2627: are using. However, it can also be installed as a cross-compiler, to 2628: compile for some other type of machine. In fact, several different 2629: configurations of GNU CC, for different target machines, can be 2630: installed side by side. Then you specify which one to use with the 2631: `\|\c 2632: .B \-b\c 2633: \&\|' option. 1.1.1.6 ! root 2634: .PP 1.1 root 2635: In addition, older and newer versions of GNU CC can be installed side 2636: by side. One of them (probably the newest) will be the default, but 2637: you may sometimes wish to use another. 2638: .TP 1.1.1.6 ! root 2639: .BI "\-b " "machine" 1.1 root 2640: The argument \c 2641: .I machine\c 2642: \& specifies the target machine for compilation. 2643: This is useful when you have installed GNU CC as a cross-compiler. 1.1.1.6 ! root 2644: .Sp 1.1 root 2645: The value to use for \c 2646: .I machine\c 2647: \& is the same as was specified as the 2648: machine type when configuring GNU CC as a cross-compiler. For 2649: example, if a cross-compiler was configured with `\|\c 2650: .B configure 2651: i386v\c 2652: \&\|', meaning to compile for an 80386 running System V, then you 2653: would specify `\|\c 2654: .B \-b i386v\c 2655: \&\|' to run that cross compiler. 1.1.1.6 ! root 2656: .Sp 1.1 root 2657: When you do not specify `\|\c 2658: .B \-b\c 2659: \&\|', it normally means to compile for 2660: the same type of machine that you are using. 2661: .TP 1.1.1.6 ! root 2662: .BI "\-V " "version" 1.1 root 2663: The argument \c 2664: .I version\c 2665: \& specifies which version of GNU CC to run. 2666: This is useful when multiple versions are installed. For example, 2667: .I version\c 2668: \& might be `\|\c 2669: .B 2.0\c 2670: \&\|', meaning to run GNU CC version 2.0. 1.1.1.6 ! root 2671: .Sp 1.1 root 2672: The default version, when you do not specify `\|\c 2673: .B \-V\c 2674: \&\|', is controlled 2675: by the way GNU CC is installed. Normally, it will be a version that 2676: is recommended for general use. 2677: .SH MACHINE DEPENDENT OPTIONS 2678: Each of the target machine types can have its own special options, 2679: starting with `\|\c 2680: .B \-m\c 2681: \&\|', to choose among various hardware models or 2682: configurations\(em\&for example, 68010 vs 68020, floating coprocessor or 2683: none. A single installed version of the compiler can compile for any 2684: model or configuration, according to the options specified. 1.1.1.6 ! root 2685: .PP 1.1.1.5 root 2686: Some configurations of the compiler also support additional special 2687: options, usually for command-line compatibility with other compilers on 2688: the same platform. 1.1.1.6 ! root 2689: .PP 1.1 root 2690: These are the `\|\c 2691: .B \-m\c 2692: \&\|' options defined for the 68000 series: 2693: .TP 1.1.1.5 root 2694: .B \-m68000 2695: .TP 2696: .B \-mc68000 2697: Generate output for a 68000. This is the default when the compiler is 2698: configured for 68000-based systems. 2699: .TP 1.1 root 2700: .B \-m68020 2701: .TP 2702: .B \-mc68020 2703: Generate output for a 68020 (rather than a 68000). This is the 1.1.1.5 root 2704: default when the compiler is configured for 68020-based systems. 1.1 root 2705: .TP 2706: .B \-m68881 2707: Generate output containing 68881 instructions for floating point. 1.1.1.6 ! root 2708: This is the default for most 68020-based systems unless 1.1.1.5 root 2709: .B \-nfp 2710: was specified when the compiler was configured. 2711: .TP 2712: .B \-m68030 2713: Generate output for a 68030. This is the default when the compiler is 2714: configured for 68030-based systems. 2715: .TP 2716: .B \-m68040 2717: Generate output for a 68040. This is the default when the compiler is 2718: configured for 68040-based systems. 2719: .TP 2720: .B \-m68020\-40 2721: Generate output for a 68040, without using any of the new instructions. 2722: This results in code which can run relatively efficiently on either a 2723: 68020/68881 or a 68030 or a 68040. 1.1 root 2724: .TP 2725: .B \-mfpa 2726: Generate output containing Sun FPA instructions for floating point. 2727: .TP 2728: .B \-msoft\-float 2729: Generate output containing library calls for floating point. 2730: .I 1.1.1.6 ! root 2731: WARNING: 1.1 root 2732: the requisite libraries are not part of GNU CC. Normally the 2733: facilities of the machine's usual C compiler are used, but this can't 2734: be done directly in cross-compilation. You must make your own 2735: arrangements to provide suitable library functions for cross-compilation. 2736: .TP 2737: .B \-mshort 2738: Consider type \c 2739: .B int\c 2740: \& to be 16 bits wide, like \c 2741: .B short int\c 2742: \&. 2743: .TP 2744: .B \-mnobitfield 2745: Do not use the bit-field instructions. `\|\c 2746: .B \-m68000\c 2747: \&\|' implies 2748: `\|\c 2749: .B \-mnobitfield\c 2750: \&\|'. 2751: .TP 2752: .B \-mbitfield 2753: Do use the bit-field instructions. `\|\c 2754: .B \-m68020\c 2755: \&\|' implies 2756: `\|\c 2757: .B \-mbitfield\c 2758: \&\|'. This is the default if you use the unmodified 2759: sources. 2760: .TP 2761: .B \-mrtd 2762: Use a different function-calling convention, in which functions 2763: that take a fixed number of arguments return with the \c 1.1.1.6 ! root 2764: .B rtd 1.1 root 2765: instruction, which pops their arguments while returning. This 2766: saves one instruction in the caller since there is no need to pop 2767: the arguments there. 1.1.1.6 ! root 2768: .Sp 1.1 root 2769: This calling convention is incompatible with the one normally 2770: used on Unix, so you cannot use it if you need to call libraries 2771: compiled with the Unix compiler. 1.1.1.6 ! root 2772: .Sp 1.1 root 2773: Also, you must provide function prototypes for all functions that 2774: take variable numbers of arguments (including \c 2775: .B printf\c 2776: \&); 2777: otherwise incorrect code will be generated for calls to those 2778: functions. 1.1.1.6 ! root 2779: .Sp 1.1 root 2780: In addition, seriously incorrect code will result if you call a 2781: function with too many arguments. (Normally, extra arguments are 2782: harmlessly ignored.) 1.1.1.6 ! root 2783: .Sp 1.1 root 2784: The \c 2785: .B rtd\c 2786: \& instruction is supported by the 68010 and 68020 2787: processors, but not by the 68000. 2788: .PP 2789: These `\|\c 2790: .B \-m\c 2791: \&\|' options are defined for the Vax: 2792: .TP 2793: .B \-munix 2794: Do not output certain jump instructions (\c 2795: .B aobleq\c 2796: \& and so on) 2797: that the Unix assembler for the Vax cannot handle across long 2798: ranges. 2799: .TP 2800: .B \-mgnu 2801: Do output those jump instructions, on the assumption that you 2802: will assemble with the GNU assembler. 2803: .TP 2804: .B \-mg 2805: Output code for g-format floating point numbers instead of d-format. 2806: .PP 2807: These `\|\c 2808: .B \-m\c 1.1.1.5 root 2809: \&\|' switches are supported on the SPARC: 2810: .PP 1.1 root 2811: .B \-mfpu 1.1.1.5 root 2812: .TP 2813: .B \-mhard\-float 1.1 root 2814: Generate output containing floating point instructions. This is the 1.1.1.5 root 2815: default. 2816: .PP 2817: .B \-mno\-fpu 1.1 root 2818: .TP 1.1.1.5 root 2819: .B \-msoft\-float 2820: Generate output containing library calls for floating point. 2821: .I Warning: 2822: there is no GNU floating-point library for SPARC. 2823: Normally the facilities of the machine's usual C compiler are used, but 2824: this cannot be done directly in cross-compilation. You must make your 2825: own arrangements to provide suitable library functions for 2826: cross-compilation. 1.1.1.6 ! root 2827: .Sp 1.1.1.5 root 2828: .B \-msoft\-float 2829: changes the calling convention in the output file; 2830: therefore, it is only useful if you compile 2831: .I all 2832: of a program with this option. 2833: .PP 1.1 root 2834: .B \-mno\-epilogue 1.1.1.5 root 2835: .TP 2836: .B \-mepilogue 2837: With 2838: .B \-mepilogue 2839: (the default), the compiler always emits code for 2840: function exit at the end of each function. Any function exit in 2841: the middle of the function (such as a return statement in C) will 2842: generate a jump to the exit code at the end of the function. 1.1.1.6 ! root 2843: .Sp 1.1.1.5 root 2844: With 2845: .BR \-mno\-epilogue , 2846: the compiler tries to emit exit code inline at every function exit. 2847: .PP 2848: .B \-mv8 2849: .TP 2850: .B \-msparclite 2851: These two options select variations on the SPARC architecture. 1.1.1.6 ! root 2852: .Sp 1.1.1.5 root 2853: By default (unless specifically configured for the Fujitsu SPARClite), 2854: GCC generates code for the v7 variant of the SPARC architecture. 1.1.1.6 ! root 2855: .Sp 1.1.1.5 root 2856: .B \-mv8 2857: will give you SPARC v8 code. The only difference from v7 2858: code is that the compiler emits the integer multiply and integer 2859: divide instructions which exist in SPARC v8 but not in SPARC v7. 1.1.1.6 ! root 2860: .Sp 1.1.1.5 root 2861: .B \-msparclite 2862: will give you SPARClite code. This adds the integer 2863: multiply, integer divide step and scan (ffs) instructions which 2864: exist in SPARClite but not in SPARC v7. 1.1 root 2865: .PP 2866: These `\|\c 2867: .B \-m\c 2868: \&\|' options are defined for the Convex: 2869: .TP 2870: .B \-mc1 2871: Generate output for a C1. This is the default when the compiler is 2872: configured for a C1. 2873: .TP 2874: .B \-mc2 2875: Generate output for a C2. This is the default when the compiler is 2876: configured for a C2. 2877: .TP 2878: .B \-margcount 2879: Generate code which puts an argument count in the word preceding each 2880: argument list. Some nonportable Convex and Vax programs need this word. 2881: (Debuggers don't, except for functions with variable-length argument 2882: lists; this info is in the symbol table.) 2883: .TP 2884: .B \-mnoargcount 2885: Omit the argument count word. This is the default if you use the 2886: unmodified sources. 2887: .PP 2888: These `\|\c 2889: .B \-m\c 2890: \&\|' options are defined for the AMD Am29000: 2891: .TP 2892: .B \-mdw 2893: Generate code that assumes the DW bit is set, i.e., that byte and 2894: halfword operations are directly supported by the hardware. This is the 2895: default. 2896: .TP 2897: .B \-mnodw 2898: Generate code that assumes the DW bit is not set. 2899: .TP 2900: .B \-mbw 2901: Generate code that assumes the system supports byte and halfword write 2902: operations. This is the default. 2903: .TP 2904: .B \-mnbw 2905: Generate code that assumes the systems does not support byte and 2906: halfword write operations. This implies `\|\c 2907: .B \-mnodw\c 2908: \&\|'. 2909: .TP 2910: .B \-msmall 2911: Use a small memory model that assumes that all function addresses are 2912: either within a single 256 KB segment or at an absolute address of less 2913: than 256K. This allows the \c 2914: .B call\c 2915: \& instruction to be used instead 2916: of a \c 2917: .B const\c 2918: \&, \c 2919: .B consth\c 2920: \&, \c 2921: .B calli\c 2922: \& sequence. 2923: .TP 2924: .B \-mlarge 2925: Do not assume that the \c 2926: .B call\c 2927: \& instruction can be used; this is the 2928: default. 2929: .TP 2930: .B \-m29050 2931: Generate code for the Am29050. 2932: .TP 2933: .B \-m29000 2934: Generate code for the Am29000. This is the default. 2935: .TP 2936: .B \-mkernel\-registers 2937: Generate references to registers \c 2938: .B gr64-gr95\c 2939: \& instead of 2940: .B gr96-gr127\c 2941: \&. This option can be used when compiling kernel code 2942: that wants a set of global registers disjoint from that used by 2943: user-mode code. 1.1.1.6 ! root 2944: .Sp 1.1 root 2945: Note that when this option is used, register names in `\|\c 2946: .B \-f\c 2947: \&\|' flags 2948: must use the normal, user-mode, names. 2949: .TP 2950: .B \-muser\-registers 2951: Use the normal set of global registers, \c 2952: .B gr96-gr127\c 2953: \&. This is the 2954: default. 2955: .TP 2956: .B \-mstack\-check 2957: Insert a call to \c 1.1.1.6 ! root 2958: .B _\|_msp_check\c 1.1 root 2959: \& after each stack adjustment. This 2960: is often used for kernel code. 2961: .PP 2962: These `\|\c 2963: .B \-m\c 2964: \&\|' options are defined for Motorola 88K architectures: 2965: .TP 1.1.1.5 root 2966: .B \-m88000 2967: Generate code that works well on both the m88100 and the 2968: m88110. 2969: .TP 2970: .B \-m88100 2971: Generate code that works best for the m88100, but that also 2972: runs on the m88110. 2973: .TP 2974: .B \-m88110 2975: Generate code that works best for the m88110, and may not run 2976: on the m88100. 1.1 root 2977: .TP 2978: .B \-midentify\-revision 2979: Include an \c 2980: .B ident\c 2981: \& directive in the assembler output recording the 2982: source file name, compiler name and version, timestamp, and compilation 2983: flags used. 2984: .TP 2985: .B \-mno\-underscores 2986: In assembler output, emit symbol names without adding an underscore 2987: character at the beginning of each name. The default is to use an 2988: underscore as prefix on each name. 2989: .TP 2990: .B \-mno\-check\-zero\-division 2991: .TP 2992: .B \-mcheck\-zero\-division 2993: Early models of the 88K architecture had problems with division by zero; 2994: in particular, many of them didn't trap. Use these options to avoid 2995: including (or to include explicitly) additional code to detect division 2996: by zero and signal an exception. All GCC configurations for the 88K use 2997: `\|\c 2998: .B \-mcheck\-zero\-division\c 2999: \&\|' by default. 3000: .TP 3001: .B \-mocs\-debug\-info 3002: .TP 3003: .B \-mno\-ocs\-debug\-info 3004: Include (or omit) additional debugging information (about 3005: registers used in each stack frame) as specified in the 88Open Object 1.1.1.6 ! root 3006: Compatibility Standard, \*(lqOCS\*(rq. This extra information is not needed 1.1 root 3007: by GDB. The default for DG/UX, SVr4, and Delta 88 SVr3.2 is to 3008: include this information; other 88k configurations omit this information 3009: by default. 3010: .TP 3011: .B \-mocs\-frame\-position 3012: .TP 3013: .B \-mno\-ocs\-frame\-position 3014: Force (or do not require) register values to be stored in a particular 3015: place in stack frames, as specified in OCS. The DG/UX, Delta88 SVr3.2, 3016: and BCS configurations use `\|\c 3017: .B \-mocs\-frame\-position\c 3018: \&\|'; other 88k 3019: configurations have the default `\|\c 3020: .B \-mno\-ocs\-frame\-position\c 3021: \&\|'. 3022: .TP 3023: .B \-moptimize\-arg\-area 3024: .TP 3025: .B \-mno\-optimize\-arg\-area 3026: Control how to store function arguments in stack frames. 3027: `\|\c 3028: .B \-moptimize\-arg\-area\c 3029: \&\|' saves space, but may break some 3030: debuggers (not GDB). `\|\c 3031: .B \-mno\-optimize\-arg\-area\c 3032: \&\|' conforms better to 3033: standards. By default GCC does not optimize the argument area. 3034: .TP 1.1.1.6 ! root 3035: .BI "\-mshort\-data\-" "num" ! 3036: .I num 1.1 root 3037: Generate smaller data references by making them relative to \c 3038: .B r0\c 3039: \&, 3040: which allows loading a value using a single instruction (rather than the 3041: usual two). You control which data references are affected by 3042: specifying \c 3043: .I num\c 3044: \& with this option. For example, if you specify 3045: `\|\c 3046: .B \-mshort\-data\-512\c 3047: \&\|', then the data references affected are those 3048: involving displacements of less than 512 bytes. 3049: `\|\c 3050: .B \-mshort\-data\-\c 3051: .I num\c 3052: \&\c 3053: \&\|' is not effective for \c 3054: .I num\c 3055: \& greater 3056: than 64K. 1.1.1.5 root 3057: .PP 3058: .B \-mserialize-volatile 1.1 root 3059: .TP 1.1.1.5 root 3060: .B \-mno-serialize-volatile 3061: Do, or do not, generate code to guarantee sequential consistency of 3062: volatile memory references. 1.1.1.6 ! root 3063: .Sp 1.1.1.5 root 3064: GNU CC always guarantees consistency by default, for the preferred 3065: processor submodel. How this is done depends on the submodel. 1.1.1.6 ! root 3066: .Sp 1.1.1.5 root 3067: The m88100 processor does not reorder memory references and so always 3068: provides sequential consistency. If you use `\|\c 3069: .B \-m88100\c 3070: \&\|', GNU CC does 3071: not generate any special instructions for sequential consistency. 1.1.1.6 ! root 3072: .Sp 1.1.1.5 root 3073: The order of memory references made by the m88110 processor does not 3074: always match the order of the instructions requesting those references. 3075: In particular, a load instruction may execute before a preceding store 3076: instruction. Such reordering violates sequential consistency of 3077: volatile memory references, when there are multiple processors. When 3078: you use `\|\c 3079: .B \-m88000\c 3080: \&\|' or `\|\c 3081: .B \-m88110\c 3082: \&\|', GNU CC generates special 3083: instructions when appropriate, to force execution in the proper order. 1.1.1.6 ! root 3084: .Sp 1.1.1.5 root 3085: The extra code generated to guarantee consistency may affect the 3086: performance of your application. If you know that you can safely forgo 3087: this guarantee, you may use the option `\|\c 3088: .B \-mno-serialize-volatile\c 3089: \&\|'. 1.1.1.6 ! root 3090: .Sp 1.1.1.5 root 3091: If you use the `\|\c 3092: .B \-m88100\c 3093: \&\|' option but require sequential consistency 3094: when running on the m88110 processor, you should use 3095: `\|\c 3096: .B \-mserialize-volatile\c 3097: \&\|'. 3098: .PP 1.1 root 3099: .B \-msvr4 3100: .TP 3101: .B \-msvr3 3102: Turn on (`\|\c 3103: .B \-msvr4\c 3104: \&\|') or off (`\|\c 3105: .B \-msvr3\c 3106: \&\|') compiler extensions 3107: related to System V release 4 (SVr4). This controls the following: 3108: .TP 1.1.1.6 ! root 3109: \ \ \ \(bu 1.1 root 3110: Which variant of the assembler syntax to emit (which you can select 3111: independently using `\|\c 1.1.1.5 root 3112: .B \-mversion\-03.00\c 1.1.1.6 ! root 3113: \&\|'). 1.1 root 3114: .TP 3115: \ \ \ \(bu 3116: `\|\c 3117: .B \-msvr4\c 3118: \&\|' makes the C preprocessor recognize `\|\c 3119: .B #pragma weak\c 3120: \&\|' 3121: .TP 3122: \ \ \ \(bu 3123: `\|\c 3124: .B \-msvr4\c 3125: \&\|' makes GCC issue additional declaration directives used in 1.1.1.6 ! root 3126: SVr4. 1.1 root 3127: .PP 3128: `\|\c 3129: .B \-msvr3\c 3130: \&\|' is the default for all m88K configurations except 3131: the SVr4 configuration. 3132: .TP 3133: .B \-mtrap\-large\-shift 3134: .TP 3135: .B \-mhandle\-large\-shift 3136: Include code to detect bit-shifts of more than 31 bits; respectively, 3137: trap such shifts or emit code to handle them properly. By default GCC 3138: makes no special provision for large bit shifts. 3139: .TP 3140: .B \-muse\-div\-instruction 3141: Very early models of the 88K architecture didn't have a divide 3142: instruction, so GCC avoids that instruction by default. Use this option 1.1.1.6 ! root 3143: to specify that it's safe to use the divide instruction. 1.1 root 3144: .TP 3145: .B \-mversion\-03.00 1.1.1.5 root 3146: In the DG/UX configuration, there are two flavors of SVr4. This option 3147: modifies 3148: .B \-msvr4 3149: to select whether the hybrid-COFF or real-ELF 3150: flavor is used. All other configurations ignore this option. 1.1 root 3151: .TP 3152: .B \-mwarn\-passed\-structs 3153: Warn when a function passes a struct as an argument or result. 3154: Structure-passing conventions have changed during the evolution of the C 3155: language, and are often the source of portability problems. By default, 3156: GCC issues no such warning. 3157: .PP 3158: These options are defined for the IBM RS6000: 3159: .PP 3160: .B \-mfp\-in\-toc 3161: .TP 3162: .B \-mno\-fp\-in\-toc 3163: Control whether or not floating-point constants go in the Table of 3164: Contents (TOC), a table of all global variable and function addresses. By 3165: default GCC puts floating-point constants there; if the TOC overflows, 3166: `\|\c 3167: .B \-mno\-fp\-in\-toc\c 3168: \&\|' will reduce the size of the TOC, which may avoid 3169: the overflow. 3170: .PP 3171: These `\|\c 3172: .B \-m\c 3173: \&\|' options are defined for the IBM RT PC: 3174: .TP 3175: .B \-min\-line\-mul 3176: Use an in-line code sequence for integer multiplies. This is the 3177: default. 3178: .TP 3179: .B \-mcall\-lib\-mul 3180: Call \c 3181: .B lmul$$\c 3182: \& for integer multiples. 3183: .TP 3184: .B \-mfull\-fp\-blocks 3185: Generate full-size floating point data blocks, including the minimum 3186: amount of scratch space recommended by IBM. This is the default. 3187: .TP 3188: .B \-mminimum\-fp\-blocks 3189: Do not include extra scratch space in floating point data blocks. This 3190: results in smaller code, but slower execution, since scratch space must 3191: be allocated dynamically. 3192: .TP 3193: .B \-mfp\-arg\-in\-fpregs 3194: Use a calling sequence incompatible with the IBM calling convention in 3195: which floating point arguments are passed in floating point registers. 3196: Note that \c 3197: .B varargs.h\c 3198: \& and \c 3199: .B stdargs.h\c 3200: \& will not work with 3201: floating point operands if this option is specified. 3202: .TP 3203: .B \-mfp\-arg\-in\-gregs 3204: Use the normal calling convention for floating point arguments. This is 3205: the default. 3206: .TP 3207: .B \-mhc\-struct\-return 3208: Return structures of more than one word in memory, rather than in a 3209: register. This provides compatibility with the MetaWare HighC (hc) 3210: compiler. Use `\|\c 3211: .B \-fpcc\-struct\-return\c 3212: \&\|' for compatibility with the 3213: Portable C Compiler (pcc). 3214: .TP 3215: .B \-mnohc\-struct\-return 3216: Return some structures of more than one word in registers, when 3217: convenient. This is the default. For compatibility with the 3218: IBM-supplied compilers, use either `\|\c 3219: .B \-fpcc\-struct\-return\c 3220: \&\|' or 3221: `\|\c 3222: .B \-mhc\-struct\-return\c 3223: \&\|'. 3224: .PP 3225: These `\|\c 3226: .B \-m\c 3227: \&\|' options are defined for the MIPS family of computers: 3228: .TP 3229: .BI "\-mcpu=" "cpu-type" 1.1.1.6 ! root 3230: Assume the defaults for the machine type 1.1 root 3231: .I cpu-type 3232: when 1.1.1.3 root 3233: scheduling instructions. The default 1.1 root 3234: .I cpu-type 3235: is 3236: .BR default , 3237: which picks the longest cycles times for any of the machines, in order 3238: that the code run at reasonable rates on all MIPS cpu's. Other 3239: choices for 3240: .I cpu-type 3241: are 3242: .BR r2000 , 3243: .BR r3000 , 3244: .BR r4000 , 3245: and 3246: .BR r6000 . 3247: While picking a specific 3248: .I cpu-type 3249: will schedule things appropriately for that particular chip, the 3250: compiler will not generate any code that does not meet level 1 of the 3251: MIPS ISA (instruction set architecture) without the 3252: .B \-mips2 3253: or 3254: .B \-mips3 3255: switches being used. 3256: .TP 3257: .B \-mips2 3258: Issue instructions from level 2 of the MIPS ISA (branch likely, square 1.1.1.6 ! root 3259: root instructions). The 1.1 root 3260: .B \-mcpu=r4000 3261: or 3262: .B \-mcpu=r6000 1.1.1.3 root 3263: switch must be used in conjunction with 1.1 root 3264: .BR \-mips2 . 3265: .TP 3266: .B \-mips3 3267: Issue instructions from level 3 of the MIPS ISA (64 bit instructions). 3268: The 3269: .B \-mcpu=r4000 1.1.1.3 root 3270: switch must be used in conjunction with 1.1 root 3271: .BR \-mips2 . 3272: .TP 3273: .B \-mint64 3274: .TP 3275: .B \-mlong64 3276: .TP 3277: .B \-mlonglong128 3278: These options don't work at present. 3279: .TP 3280: .B \-mmips\-as 3281: Generate code for the MIPS assembler, and invoke 3282: .B mips\-tfile 3283: to add normal debug information. This is the default for all 3284: platforms except for the OSF/1 reference platform, using the OSF/rose 1.1.1.2 root 3285: object format. If any of the 1.1 root 3286: .BR \-ggdb , 3287: .BR \-gstabs , 3288: or 3289: .B \-gstabs+ 3290: switches are used, the 3291: .B mips\-tfile 3292: program will encapsulate the stabs within MIPS ECOFF. 3293: .TP 3294: .B \-mgas 3295: Generate code for the GNU assembler. This is the default on the OSF/1 3296: reference platform, using the OSF/rose object format. 3297: .TP 3298: .B \-mrnames 3299: .TP 3300: .B \-mno\-rnames 3301: The 3302: .B \-mrnames 3303: switch says to output code using the MIPS software names for the 1.1.1.6 ! root 3304: registers, instead of the hardware names (ie, 1.1 root 3305: .B a0 3306: instead of 3307: .BR $4 ). 3308: The GNU assembler does not support the 3309: .B \-mrnames 3310: switch, and the MIPS assembler will be instructed to run the MIPS C 3311: preprocessor over the source file. The 3312: .B \-mno\-rnames 3313: switch is default. 3314: .TP 3315: .B \-mgpopt 3316: .TP 3317: .B \-mno\-gpopt 3318: The 3319: .B \-mgpopt 3320: switch says to write all of the data declarations before the 3321: instructions in the text section, to all the MIPS assembler to 3322: generate one word memory references instead of using two words for 3323: short global or static data items. This is on by default if 3324: optimization is selected. 3325: .TP 3326: .B \-mstats 3327: .TP 3328: .B \-mno\-stats 3329: For each non-inline function processed, the 3330: .B \-mstats 3331: switch causes the compiler to emit one line to the standard error file 3332: to print statistics about the program (number of registers saved, 3333: stack size, etc.). 3334: .TP 3335: .B \-mmemcpy 3336: .TP 3337: .B \-mno\-memcpy 3338: The 3339: .B \-mmemcpy 3340: switch makes all block moves call the appropriate string function 3341: .RB ( memcpy 3342: or 3343: .BR bcopy ) 3344: instead of possibly generating inline code. 3345: .TP 3346: .B \-mmips\-tfile 3347: .TP 3348: .B \-mno\-mips\-tfile 3349: The 3350: .B \-mno\-mips\-tfile 3351: switch causes the compiler not postprocess the object file with the 3352: .B mips\-tfile 3353: program, after the MIPS assembler has generated it to add debug 3354: support. If 3355: .B mips\-tfile 3356: is not run, then no local variables will be available to the debugger. 3357: In addition, 3358: .B stage2 3359: and 3360: .B stage3 3361: objects will have the temporary file names passed to the assembler 3362: embedded in the object file, which means the objects will not compare 3363: the same. 3364: .TP 3365: .B \-msoft\-float 3366: Generate output containing library calls for floating point. 3367: .I 1.1.1.6 ! root 3368: WARNING: 1.1 root 3369: the requisite libraries are not part of GNU CC. Normally the 3370: facilities of the machine's usual C compiler are used, but this can't 3371: be done directly in cross-compilation. You must make your own 3372: arrangements to provide suitable library functions for cross-compilation. 3373: .TP 3374: .B \-mhard\-float 3375: Generate output containing floating point instructions. This is the 3376: default if you use the unmodified sources. 3377: .TP 3378: .B \-mfp64 3379: Assume that the 3380: .B FR 3381: bit in the status word is on, and that there are 32 64-bit floating 3382: point registers, instead of 32 32-bit floating point registers. You 3383: must also specify the 3384: .B \-mcpu=r4000 3385: and 3386: .B \-mips3 3387: switches. 3388: .TP 3389: .B \-mfp32 3390: Assume that there are 32 32-bit floating point registers. This is the 3391: default. 1.1.1.5 root 3392: .PP 1.1 root 3393: .B \-mabicalls 1.1.1.5 root 3394: .TP 3395: .B \-mno\-abicalls 3396: Emit (or do not emit) the 1.1 root 3397: .BR \&.abicalls , 3398: .BR \&.cpload , 3399: and 3400: .B \&.cprestore 3401: pseudo operations that some System V.4 ports use for position 3402: independent code. 3403: .TP 3404: .B \-mhalf\-pic 3405: .TP 3406: .B \-mno\-half\-pic 3407: The 3408: .B \-mhalf\-pic 3409: switch says to put pointers to extern references into the data section 3410: and load them up, rather than put the references in the text section. 3411: This option does not work at present. 3412: .B 3413: .BI \-G num 1.1.1.6 ! root 3414: Put global and static items less than or equal to 1.1 root 3415: .I num 3416: bytes into the small data or bss sections instead of the normal data 3417: or bss section. This allows the assembler to emit one word memory 3418: reference instructions based on the global pointer 3419: .RB ( gp 3420: or 3421: .BR $28 ), 3422: instead of the normal two words used. By default, 3423: .I num 3424: is 8 when the MIPS assembler is used, and 0 when the GNU 3425: assembler is used. The 3426: .BI \-G num 3427: switch is also passed to the assembler and linker. All modules should 3428: be compiled with the same 3429: .BI \-G num 3430: value. 1.1.1.5 root 3431: .TP 3432: .B \-nocpp 3433: Tell the MIPS assembler to not run it's preprocessor over user 3434: assembler files (with a `\|\c 3435: .B .s\c 3436: \&\|' suffix) when assembling them. 3437: .PP 3438: These `\|\c 3439: .B \-m\c 3440: \&\|' options are defined for the Intel 80386 family of computers: 3441: .B \-m486 3442: .TP 3443: .B \-mno\-486 3444: Control whether or not code is optimized for a 486 instead of an 3445: 386. Code generated for a 486 will run on a 386 and vice versa. 3446: .TP 3447: .B \-msoft\-float 3448: Generate output containing library calls for floating point. 3449: .I Warning: 3450: the requisite libraries are not part of GNU CC. 3451: Normally the facilities of the machine's usual C compiler are used, but 3452: this can't be done directly in cross-compilation. You must make your 3453: own arrangements to provide suitable library functions for 3454: cross-compilation. 1.1.1.6 ! root 3455: .Sp 1.1.1.5 root 3456: On machines where a function returns floating point results in the 80387 3457: register stack, some floating point opcodes may be emitted even if 3458: `\|\c 3459: .B \-msoft-float\c 3460: \&\|' is used. 3461: .TP 3462: .B \-mno-fp-ret-in-387 3463: Do not use the FPU registers for return values of functions. 1.1.1.6 ! root 3464: .Sp 1.1.1.5 root 3465: The usual calling convention has functions return values of types 3466: .B float\c 3467: \& and \c 3468: .B double\c 3469: \& in an FPU register, even if there 3470: is no FPU. The idea is that the operating system should emulate 3471: an FPU. 1.1.1.6 ! root 3472: .Sp 1.1.1.5 root 3473: The option `\|\c 3474: .B \-mno-fp-ret-in-387\c 3475: \&\|' causes such values to be returned 3476: in ordinary CPU registers instead. 3477: .PP 3478: These `\|\c 3479: .B \-m\c 3480: \&\|' options are defined for the HPPA family of computers: 3481: .TP 3482: .B \-mpa-risc-1-0 3483: Generate code for a PA 1.0 processor. 3484: .TP 3485: .B \-mpa-risc-1-1 3486: Generate code for a PA 1.1 processor. 3487: .TP 3488: .B \-mkernel 3489: Generate code which is suitable for use in kernels. Specifically, avoid 3490: .B add\c 3491: \& instructions in which one of the arguments is the DP register; 3492: generate \c 3493: .B addil\c 3494: \& instructions instead. This avoids a rather serious 3495: bug in the HP-UX linker. 3496: .TP 3497: .B \-mshared-libs 3498: Generate code that can be linked against HP-UX shared libraries. This option 3499: is not fully function yet, and is not on by default for any PA target. Using 3500: this option can cause incorrect code to be generated by the compiler. 3501: .TP 3502: .B \-mno-shared-libs 3503: Don't generate code that will be linked against shared libraries. This is 3504: the default for all PA targets. 3505: .TP 3506: .B \-mlong-calls 3507: Generate code which allows calls to functions greater than 256K away from 3508: the caller when the caller and callee are in the same source file. Do 1.1.1.6 ! root 3509: not turn this option on unless code refuses to link with \*(lqbranch out of ! 3510: range errors\*('' from the linker. 1.1.1.5 root 3511: .TP 3512: .B \-mdisable-fpregs 3513: Prevent floating point registers from being used in any manner. This is 3514: necessary for compiling kernels which perform lazy context switching of 3515: floating point registers. If you use this option and attempt to perform 3516: floating point operations, the compiler will abort. 3517: .TP 3518: .B \-mdisable-indexing 3519: Prevent the compiler from using indexing address modes. This avoids some 3520: rather obscure problems when compiling MIG generated code under MACH. 3521: .TP 3522: .B \-mtrailing-colon 3523: Add a colon to the end of label definitions (for ELF assemblers). 3524: .PP 3525: These `\|\c 3526: .B \-m\c 3527: \&\|' options are defined for the Intel 80960 family of computers: 3528: .TP 3529: .BI "\-m" "cpu-type" 3530: Assume the defaults for the machine type 3531: .I cpu-type 3532: for instruction and addressing-mode availability and alignment. 3533: The default 3534: .I cpu-type 3535: is 3536: .BR kb ; 3537: other choices are 3538: .BR ka , 3539: .BR mc , 3540: .BR ca , 3541: .BR cf , 3542: .BR sa , 3543: and 3544: .BR sb . 3545: .TP 3546: .B \-mnumerics 3547: .TP 3548: .B \-msoft\-float 1.1.1.6 ! root 3549: The 1.1.1.5 root 3550: .B \-mnumerics 3551: option indicates that the processor does support 1.1.1.6 ! root 3552: floating-point instructions. The 1.1.1.5 root 3553: .B \-msoft\-float 3554: option indicates 3555: that floating-point support should not be assumed. 3556: .TP 3557: .B \-mleaf\-procedures 3558: .TP 3559: .B \-mno\-leaf\-procedures 3560: Do (or do not) attempt to alter leaf procedures to be callable with the 3561: .I bal 3562: instruction as well as 3563: .IR call . 3564: This will result in more 3565: efficient code for explicit calls when the 3566: .I bal 3567: instruction can be 3568: substituted by the assembler or linker, but less efficient code in other 3569: cases, such as calls via function pointers, or using a linker that doesn't 3570: support this optimization. 3571: .TP 3572: .B \-mtail\-call 3573: .TP 3574: .B \-mno\-tail\-call 3575: Do (or do not) make additional attempts (beyond those of the 3576: machine-independent portions of the compiler) to optimize tail-recursive 3577: calls into branches. You may not want to do this because the detection of 3578: cases where this is not valid is not totally complete. The default is 3579: .BR \-mno\-tail\-call . 3580: .TP 3581: .B \-mcomplex\-addr 3582: .TP 3583: .B \-mno\-complex\-addr 3584: Assume (or do not assume) that the use of a complex addressing mode is a 3585: win on this implementation of the i960. Complex addressing modes may not 3586: be worthwhile on the K-series, but they definitely are on the C-series. 1.1.1.6 ! root 3587: The default is currently 1.1.1.5 root 3588: .B \-mcomplex\-addr 3589: for all processors except 3590: the CB and CC. 3591: .TP 3592: .B \-mcode\-align 3593: .TP 3594: .B \-mno\-code\-align 3595: Align code to 8-byte boundaries for faster fetching (or don't bother). 3596: Currently turned on by default for C-series implementations only. 3597: .TP 3598: .B \-mic\-compat 3599: .TP 3600: .B \-mic2.0\-compat 3601: .TP 3602: .B \-mic3.0\-compat 3603: Enable compatibility with iC960 v2.0 or v3.0. 3604: .TP 3605: .B \-masm\-compat 3606: .TP 3607: .B \-mintel\-asm 3608: Enable compatibility with the iC960 assembler. 3609: .TP 3610: .B \-mstrict\-align 3611: .TP 3612: .B \-mno\-strict\-align 3613: Do not permit (do permit) unaligned accesses. 3614: .TP 3615: .B \-mold\-align 3616: Enable structure-alignment compatibility with Intel's gcc release version 3617: 1.3 (based on gcc 1.37). Currently this is buggy in that 3618: .B #pragma align 1 3619: is always assumed as well, and cannot be turned off. 3620: .PP 3621: These `\|\c 3622: .B \-m\c 3623: \&\|' options are defined for the DEC Alpha implementations: 3624: .TP 3625: .B \-mno-soft-float 3626: .TP 3627: .B \-msoft-float 3628: Use (do not use) the hardware floating-point instructions for 3629: floating-point operations. When \c 3630: .B \-msoft-float\c 3631: \& is specified, 3632: functions in `\|\c 3633: .B libgcc1.c\c 3634: \&\|' will be used to perform floating-point 3635: operations. Unless they are replaced by routines that emulate the 3636: floating-point operations, or compiled in such a way as to call such 3637: emulations routines, these routines will issue floating-point 3638: operations. If you are compiling for an Alpha without floating-point 3639: operations, you must ensure that the library is built so as not to call 3640: them. 1.1.1.6 ! root 3641: .Sp 1.1.1.5 root 3642: Note that Alpha implementations without floating-point operations are 3643: required to have floating-point registers. 3644: .TP 3645: .B \-mfp-reg 3646: .TP 3647: .B \-mno-fp-regs 3648: Generate code that uses (does not use) the floating-point register set. 3649: .B \-mno-fp-regs\c 3650: \& implies \c 3651: .B \-msoft-float\c 3652: \&. If the floating-point 3653: register set is not used, floating point operands are passed in integer 3654: registers as if they were integers and floating-point results are passed 3655: in $0 instead of $f0. This is a non-standard calling sequence, so any 3656: function with a floating-point argument or return value called by code 3657: compiled with \c 3658: .B \-mno-fp-regs\c 3659: \& must also be compiled with that 3660: option. 1.1.1.6 ! root 3661: .Sp 1.1.1.5 root 3662: A typical use of this option is building a kernel that does not use, 3663: and hence need not save and restore, any floating-point registers. 3664: .PP 3665: These additional options are available on System V Release 4 for 3666: compatibility with other compilers on those systems: 3667: .TP 3668: .B \-G 3669: On SVr4 systems, \c 3670: .B gcc\c 3671: \& accepts the option `\|\c 3672: .B \-G\c 3673: \&\|' (and passes 3674: it to the system linker), for compatibility with other compilers. 3675: However, we suggest you use `\|\c 3676: .B \-symbolic\c 3677: \&\|' or `\|\c 3678: .B \-shared\c 3679: \&\|' as 3680: appropriate, instead of supplying linker options on the \c 1.1.1.6 ! root 3681: .B gcc 1.1.1.5 root 3682: command line. 3683: .TP 3684: .B \-Qy 3685: Identify the versions of each tool used by the compiler, in a 3686: .B .ident\c 3687: \& assembler directive in the output. 3688: .TP 3689: .B \-Qn 3690: Refrain from adding \c 3691: .B .ident\c 3692: \& directives to the output file (this is 3693: the default). 3694: .TP 1.1.1.6 ! root 3695: .BI "\-YP," "dirs" 1.1.1.5 root 3696: Search the directories \c 3697: .I dirs\c 3698: \&, and no others, for libraries 3699: specified with `\|\c 3700: .B \-l\c 3701: \&\|'. You can separate directory entries in 3702: .I dirs\c 3703: \& from one another with colons. 3704: .TP 1.1.1.6 ! root 3705: .BI "\-Ym," "dir" 1.1.1.5 root 3706: Look in the directory \c 3707: .I dir\c 3708: \& to find the M4 preprocessor. 3709: The assembler uses this option. 1.1 root 3710: .SH CODE GENERATION OPTIONS 3711: These machine-independent options control the interface conventions 3712: used in code generation. 1.1.1.6 ! root 3713: .PP 1.1 root 3714: Most of them begin with `\|\c 3715: \-f\c 3716: \&\|'. These options have both positive and negative forms; the negative form 3717: of `\|\c 3718: .B \-ffoo\c 3719: \&\|' would be `\|\c 3720: .B \-fno\-foo\c 3721: \&\|'. In the table below, only 3722: one of the forms is listed\(em\&the one which is not the default. You 3723: can figure out the other form by either removing `\|\c 3724: .B no\-\c 3725: \&\|' or adding 3726: it. 3727: .TP 3728: .B \-fnonnull\-objects 1.1.1.5 root 3729: Assume that objects reached through references are not null 3730: (C++ only). 1.1.1.6 ! root 3731: .Sp 1.1 root 3732: Normally, GNU C++ makes conservative assumptions about objects reached 1.1.1.5 root 3733: through references. For example, the compiler must check that \c 1.1.1.6 ! root 3734: .B a 1.1.1.5 root 3735: is not null in code like the following: 1.1.1.6 ! root 3736: .Sp ! 3737: obj &a = g (); ! 3738: a.f (2); ! 3739: .Sp 1.1 root 3740: Checking that references of this sort have non-null values requires 3741: extra code, however, and it is unnecessary for many programs. You can 3742: use `\|\c 1.1.1.5 root 3743: .B \-fnonnull-objects\c 3744: \&\|' to omit the checks for null, if your 3745: program doesn't require checking. 1.1 root 3746: .TP 3747: .B \-fpcc\-struct\-return 3748: Use the same convention for returning \c 3749: .B struct\c 3750: \& and \c 1.1.1.6 ! root 3751: .B union 1.1 root 3752: values that is used by the usual C compiler on your system. This 3753: convention is less efficient for small structures, and on many 3754: machines it fails to be reentrant; but it has the advantage of 3755: allowing intercallability between GCC-compiled code and PCC-compiled 3756: code. 3757: .TP 1.1.1.5 root 3758: .B \-freg\-struct\-return 3759: Use the convention that 3760: .B struct 3761: and 3762: .B union 3763: values are returned in registers when possible. This is more 3764: efficient for small structures than 3765: .BR \-fpcc\-struct\-return . 1.1.1.6 ! root 3766: .Sp 1.1.1.5 root 3767: If you specify neither 3768: .B \-fpcc\-struct\-return 3769: nor 3770: .BR \-freg\-struct\-return , 3771: GNU CC defaults to whichever convention is standard for the target. 3772: If there is no standard convention, GNU CC defaults to 3773: .BR \-fpcc\-struct\-return . 3774: .TP 1.1 root 3775: .B \-fshort\-enums 3776: Allocate to an \c 3777: .B enum\c 3778: \& type only as many bytes as it needs for the 3779: declared range of possible values. Specifically, the \c 3780: .B enum\c 3781: \& type 3782: will be equivalent to the smallest integer type which has enough room. 3783: .TP 3784: .B \-fshort\-double 3785: Use the same size for 3786: .B double 3787: as for 3788: .B float 3789: \&. 3790: .TP 3791: .B \-fshared\-data 3792: Requests that the data and non-\c 3793: .B const\c 3794: \& variables of this 3795: compilation be shared data rather than private data. The distinction 3796: makes sense only on certain operating systems, where shared data is 3797: shared between processes running the same program, while private data 3798: exists in one copy per process. 3799: .TP 3800: .B \-fno\-common 3801: Allocate even uninitialized global variables in the bss section of the 3802: object file, rather than generating them as common blocks. This has the 3803: effect that if the same variable is declared (without \c 3804: .B extern\c 3805: \&) in 3806: two different compilations, you will get an error when you link them. 3807: The only reason this might be useful is if you wish to verify that the 3808: program will work on other systems which always work this way. 3809: .TP 1.1.1.5 root 3810: .B \-fno\-ident 3811: Ignore the `\|\c 3812: .B #ident\c 3813: \&\|' directive. 3814: .TP 3815: .B \-fno\-gnu\-linker 3816: Do not output global initializations (such as C++ constructors and 3817: destructors) in the form used by the GNU linker (on systems where the GNU 3818: linker is the standard method of handling them). Use this option when 3819: you want to use a non-GNU linker, which also requires using the 3820: .B collect2\c 3821: \& program to make sure the system linker includes 3822: constructors and destructors. (\c 3823: .B collect2\c 3824: \& is included in the GNU CC 3825: distribution.) For systems which \c 3826: .I must\c 3827: \& use \c 3828: .B collect2\c 3829: \&, the 3830: compiler driver \c 3831: .B gcc\c 3832: \& is configured to do this automatically. 3833: .TP 3834: .B \-finhibit-size-directive 3835: Don't output a \c 3836: .B .size\c 3837: \& assembler directive, or anything else that 1.1.1.6 ! root 3838: would cause trouble if the function is split in the middle, and the 1.1.1.5 root 3839: two halves are placed at locations far apart in memory. This option is 3840: used when compiling `\|\c 3841: .B crtstuff.c\c 3842: \&\|'; you should not need to use it 3843: for anything else. 3844: .TP 3845: .B \-fverbose-asm 3846: Put extra commentary information in the generated assembly code to 3847: make it more readable. This option is generally only of use to those 3848: who actually need to read the generated assembly code (perhaps while 3849: debugging the compiler itself). 3850: .TP 1.1 root 3851: .B \-fvolatile 3852: Consider all memory references through pointers to be volatile. 3853: .TP 1.1.1.5 root 3854: .B \-fvolatile\-global 3855: Consider all memory references to extern and global data items to 3856: be volatile. 3857: .TP 1.1 root 3858: .B \-fpic 3859: If supported for the target machines, generate position-independent code, 3860: suitable for use in a shared library. 3861: .TP 3862: .B \-fPIC 3863: If supported for the target machine, emit position-independent code, 3864: suitable for dynamic linking, even if branches need large displacements. 3865: .TP 1.1.1.6 ! root 3866: .BI "\-ffixed\-" "reg" 1.1 root 3867: Treat the register named \c 3868: .I reg\c 3869: \& as a fixed register; generated code 3870: should never refer to it (except perhaps as a stack pointer, frame 3871: pointer or in some other fixed role). 1.1.1.6 ! root 3872: .Sp 1.1 root 3873: .I reg\c 3874: \& must be the name of a register. The register names accepted 3875: are machine-specific and are defined in the \c 1.1.1.6 ! root 3876: .B REGISTER_NAMES 1.1 root 3877: macro in the machine description macro file. 1.1.1.6 ! root 3878: .Sp 1.1 root 3879: This flag does not have a negative form, because it specifies a 3880: three-way choice. 3881: .TP 1.1.1.6 ! root 3882: .BI "\-fcall\-used\-" "reg" 1.1 root 3883: Treat the register named \c 3884: .I reg\c 3885: \& as an allocatable register that is 3886: clobbered by function calls. It may be allocated for temporaries or 3887: variables that do not live across a call. Functions compiled this way 3888: will not save and restore the register \c 3889: .I reg\c 3890: \&. 1.1.1.6 ! root 3891: .Sp 1.1 root 3892: Use of this flag for a register that has a fixed pervasive role in the 3893: machine's execution model, such as the stack pointer or frame pointer, 3894: will produce disastrous results. 1.1.1.6 ! root 3895: .Sp 1.1 root 3896: This flag does not have a negative form, because it specifies a 3897: three-way choice. 3898: .TP 1.1.1.6 ! root 3899: .BI "\-fcall\-saved\-" "reg" 1.1 root 3900: Treat the register named \c 3901: .I reg\c 3902: \& as an allocatable register saved by 3903: functions. It may be allocated even for temporaries or variables that 3904: live across a call. Functions compiled this way will save and restore 3905: the register \c 3906: .I reg\c 3907: \& if they use it. 1.1.1.6 ! root 3908: .Sp 1.1 root 3909: Use of this flag for a register that has a fixed pervasive role in the 3910: machine's execution model, such as the stack pointer or frame pointer, 3911: will produce disastrous results. 1.1.1.6 ! root 3912: .Sp 1.1 root 3913: A different sort of disaster will result from the use of this flag for 3914: a register in which function values may be returned. 1.1.1.6 ! root 3915: .Sp 1.1 root 3916: This flag does not have a negative form, because it specifies a 3917: three-way choice. 3918: .SH PRAGMAS 3919: Two `\|\c 3920: .B #pragma\c 3921: \&\|' directives are supported for GNU C++, to permit using the same 3922: header file for two purposes: as a definition of interfaces to a given 3923: object class, and as the full definition of the contents of that object class. 3924: .TP 3925: .B #pragma interface 1.1.1.5 root 3926: (C++ only.) 1.1 root 3927: Use this directive in header files that define object classes, to save 3928: space in most of the object files that use those classes. Normally, 3929: local copies of certain information (backup copies of inline member 3930: functions, debugging information, and the internal tables that 3931: implement virtual functions) must be kept in each object file that 3932: includes class definitions. You can use this pragma to avoid such 3933: duplication. When a header file containing `\|\c 3934: .B #pragma interface\c 3935: \&\|' is included in a compilation, this auxiliary information 3936: will not be generated (unless the main input source file itself uses 3937: `\|\c 3938: .B #pragma implementation\c 3939: \&\|'). Instead, the object files will contain references to be 1.1.1.6 ! root 3940: resolved at link time. 1.1 root 3941: .TP 3942: .B #pragma implementation 3943: .TP 1.1.1.6 ! root 3944: \fB#pragma implementation "\fP\fIobjects\fP\fB.h"\fP 1.1.1.5 root 3945: (C++ only.) 1.1 root 3946: Use this pragma in a main input file, when you want full output from 3947: included header files to be generated (and made globally visible). 3948: The included header file, in turn, should use `\|\c 3949: .B #pragma interface\c 1.1.1.6 ! root 3950: \&\|'. 1.1 root 3951: Backup copies of inline member functions, debugging information, and 3952: the internal tables used to implement virtual functions are all 3953: generated in implementation files. 1.1.1.6 ! root 3954: .Sp 1.1 root 3955: If you use `\|\c 3956: .B #pragma implementation\c 3957: \&\|' with no argument, it applies to an include file with the same 3958: basename as your source file; for example, in `\|\c 3959: .B allclass.cc\c 3960: \&\|', `\|\c 3961: .B #pragma implementation\c 3962: \&\|' by itself is equivalent to `\|\c 1.1.1.6 ! root 3963: .B 1.1 root 3964: #pragma implementation "allclass.h"\c 3965: \&\|'. Use the string argument if you want a single implementation 1.1.1.6 ! root 3966: file to include code from multiple header files. ! 3967: .Sp 1.1 root 3968: There is no way to split up the contents of a single header file into 1.1.1.6 ! root 3969: multiple implementation files. 1.1 root 3970: .SH FILES 1.1.1.6 ! root 3971: .nf 1.1 root 3972: .ta \w'LIBDIR/g++\-include 'u 3973: file.c C source file 3974: file.h C header (preprocessor) file 3975: file.i preprocessed C source file 3976: file.C C++ source file 3977: file.cc C++ source file 3978: file.cxx C++ source file 3979: file.m Objective-C source file 3980: file.s assembly language file 3981: file.o object file 3982: a.out link edited output 3983: \fITMPDIR\fR/cc\(** temporary files 3984: \fILIBDIR\fR/cpp preprocessor 3985: \fILIBDIR\fR/cc1 compiler for C 3986: \fILIBDIR\fR/cc1plus compiler for C++ 3987: \fILIBDIR\fR/collect linker front end needed on some machines 3988: \fILIBDIR\fR/libgcc.a GCC subroutine library 3989: /lib/crt[01n].o start-up routine 3990: \fILIBDIR\fR/ccrt0 additional start-up routine for C++ 3991: /lib/libc.a standard C library, see 3992: .IR intro (3) 1.1.1.6 ! root 3993: /usr/include standard directory for \fB#include\fP files ! 3994: \fILIBDIR\fR/include standard gcc directory for \fB#include\fP files ! 3995: \fILIBDIR\fR/g++\-include additional g++ directory for \fB#include\fP ! 3996: .Sp ! 3997: .fi 1.1 root 3998: .I LIBDIR 3999: is usually 4000: .B /usr/local/lib/\c 4001: .IR machine / version . 4002: .br 4003: .I TMPDIR 1.1.1.6 ! root 4004: comes from the environment variable 1.1 root 4005: .B TMPDIR 4006: (default 4007: .B /usr/tmp 4008: if available, else 4009: .B /tmp\c 4010: \&). 4011: .SH "SEE ALSO" 4012: cpp(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1). 4013: .br 1.1.1.6 ! root 4014: .RB "`\|" gcc "\|', `\|" cpp \|', ! 4015: .RB "`\|" as "\|', `\|" ld \|', ! 4016: and 1.1 root 4017: .RB `\| gdb \|' 4018: entries in 4019: .B info\c 4020: \&. 4021: .br 1.1.1.6 ! root 4022: .I 1.1 root 4023: Using and Porting GNU CC (for version 2.0)\c 1.1.1.6 ! root 4024: , Richard M. Stallman; 1.1 root 4025: .I 4026: The C Preprocessor\c 1.1.1.5 root 4027: , Richard M. Stallman; 1.1.1.6 ! root 4028: .I 1.1.1.5 root 4029: Debugging with GDB: the GNU Source-Level Debugger\c 4030: , Richard M. Stallman and Roland H. Pesch; 1.1 root 4031: .I 4032: Using as: the GNU Assembler\c 1.1.1.5 root 4033: , Dean Elsner, Jay Fenlason & friends; 1.1 root 4034: .I 1.1.1.5 root 4035: ld: the GNU linker\c 4036: , Steve Chamberlain and Roland Pesch. 1.1 root 4037: .SH BUGS 1.1.1.5 root 4038: For instructions on reporting bugs, see the GCC manual. 1.1 root 4039: .SH COPYING 1.1.1.6 ! root 4040: Copyright ! 4041: .if t \(co ! 4042: 1991, 1992, 1993 Free Software Foundation, Inc. 1.1 root 4043: .PP 4044: Permission is granted to make and distribute verbatim copies of 4045: this manual provided the copyright notice and this permission notice 4046: are preserved on all copies. 4047: .PP 4048: Permission is granted to copy and distribute modified versions of this 4049: manual under the conditions for verbatim copying, provided that the 4050: entire resulting derived work is distributed under the terms of a 4051: permission notice identical to this one. 4052: .PP 4053: Permission is granted to copy and distribute translations of this 4054: manual into another language, under the above conditions for modified 4055: versions, except that this permission notice may be included in 4056: translations approved by the Free Software Foundation instead of in 4057: the original English. 4058: .SH AUTHORS 4059: See the GNU CC Manual for the contributors to GNU CC.
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