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1.1 ! root 1: .\" Copyright (c) 1983 Regents of the University of California. ! 2: .\" All rights reserved. The Berkeley software License Agreement ! 3: .\" specifies the terms and conditions for redistribution. ! 4: .\" ! 5: .\" @(#)tty.4 6.8 (Berkeley) 2/24/89 ! 6: .\" ! 7: .TH TTY 4 "February 24, 1989" ! 8: .UC 4 ! 9: .SH NAME ! 10: tty \- general terminal interface ! 11: .SH SYNOPSIS ! 12: .B #include <sgtty.h> ! 13: .SH DESCRIPTION ! 14: This section describes ! 15: both a particular special file ! 16: .B /dev/tty ! 17: and the terminal drivers used for conversational computing. ! 18: .LP ! 19: .B Line disciplines. ! 20: .PP ! 21: The system provides different ! 22: .I "line disciplines" ! 23: for controlling communications lines. ! 24: In this version of the system there are two disciplines available for use ! 25: with terminals: ! 26: .IP "old" 8 ! 27: The old (Version 7) terminal driver. This is sometimes used when using the ! 28: standard shell ! 29: .IR sh (1). ! 30: .IP "new" ! 31: The standard Berkeley terminal driver, with features for job control; ! 32: this must be used when using ! 33: .IR csh (1). ! 34: .LP ! 35: Line discipline switching is accomplished with the TIOCSETD ! 36: .IR ioctl : ! 37: .IP ! 38: .B "int ldisc = LDISC;" ! 39: .br ! 40: .B "ioctl(f, TIOCSETD, &ldisc);" ! 41: .LP ! 42: where LDISC is OTTYDISC for the standard tty driver ! 43: and NTTYDISC for the ``new'' driver. ! 44: The standard (currently old) tty driver is discipline 0 by convention. ! 45: Other disciplines may exist for special purposes, such as use of communications ! 46: lines for network connections. ! 47: The current line discipline can be obtained with the TIOCGETD ! 48: .IR ioctl . ! 49: Pending input is discarded when the line discipline is changed. ! 50: .PP ! 51: All of the low-speed asynchronous ! 52: communications ports can use any ! 53: of the available line disciplines, no matter what ! 54: hardware is involved. ! 55: The remainder of this section discusses the ! 56: \*(lqold\*(rq and \*(lqnew\*(rq disciplines. ! 57: .LP ! 58: .B "The control terminal." ! 59: .LP ! 60: When a terminal file is opened, it causes the process to wait until a ! 61: connection is established. In practice, user programs seldom open ! 62: these files; they are opened by ! 63: .IR getty (8) ! 64: or ! 65: .IR rlogind (8C) ! 66: and become a user's standard input and output file. ! 67: .PP ! 68: If a process which has no control terminal opens a terminal file, then ! 69: that terminal file becomes the control terminal for that process. ! 70: The control terminal is thereafter inherited by a child process during a ! 71: .IR fork (2), ! 72: even if the control terminal is closed. ! 73: .LP ! 74: The file ! 75: .B /dev/tty ! 76: is, in each process, a synonym for a ! 77: .I "control terminal" ! 78: associated with that process. It is useful for programs that wish to ! 79: be sure of writing messages on the terminal ! 80: no matter how output has been redirected. ! 81: It can also be used for programs that demand a file name ! 82: for output, when typed output is desired ! 83: and it is tiresome to find out which terminal ! 84: is currently in use. ! 85: .LP ! 86: A process can remove the association it has with its controlling ! 87: terminal by opening the file ! 88: .B /dev/tty ! 89: and issuing an ! 90: .IP ! 91: .B "ioctl(f, TIOCNOTTY, 0);" ! 92: .LP ! 93: This is often desirable in server processes. ! 94: .LP ! 95: .B "Process groups." ! 96: .LP ! 97: Command processors such as ! 98: .IR csh (1) ! 99: can arbitrate the terminal between different ! 100: .I jobs ! 101: by placing related jobs in a single process group and associating this ! 102: process group with the terminal. A terminal's associated process group ! 103: may be set using the TIOCSPGRP ! 104: .IR ioctl (2): ! 105: .IP ! 106: .B "ioctl(fildes, TIOCSPGRP, &pgrp);" ! 107: .LP ! 108: or examined using TIOCGPGRP, which returns the current ! 109: process group in ! 110: .IR pgrp . ! 111: The new terminal driver aids in this arbitration by restricting access ! 112: to the terminal by processes which are not in the current process group; ! 113: see ! 114: .B "Job access control" ! 115: below. ! 116: .LP ! 117: .B "Modes." ! 118: .PP ! 119: The terminal drivers have three major modes, characterized by the ! 120: amount of processing on the input and output characters: ! 121: .IP cooked 10 ! 122: The normal mode. In this mode lines of input are collected and input editing ! 123: is done. The edited line is made available when it is completed by ! 124: a newline, ! 125: or when the \fIt_brkc\fP character (normally undefined) ! 126: or \fIt_eofc\fP character (normally an EOT, control-D, hereafter ^D) ! 127: is entered. ! 128: A carriage return is usually made synonymous with newline in this mode, ! 129: and replaced with a newline whenever it is typed. ! 130: All driver functions ! 131: (input editing, interrupt generation, ! 132: output processing such as delay generation and tab expansion, etc.) ! 133: are available in this mode. ! 134: .IP CBREAK 10 ! 135: This mode eliminates the character, word, and line editing input facilities, ! 136: making the input character available to the user program as it is typed. ! 137: Flow control, literal-next and interrupt processing are still done in this mode. ! 138: Output processing is done. ! 139: .IP RAW 10 ! 140: This mode eliminates all input processing and makes all input characters ! 141: available as they are typed; no output processing is done either. ! 142: .PP ! 143: The style of input processing can also be very different when ! 144: the terminal is put in non-blocking I/O mode; see ! 145: the FNDELAY flag described in ! 146: .IR fcntl (2). ! 147: In this case a ! 148: .IR read (2) ! 149: from the control terminal will never block, but rather ! 150: return an error indication (EWOULDBLOCK) if there is no ! 151: input available. ! 152: .PP ! 153: A process may also request that a SIGIO signal be sent it whenever input ! 154: is present and also whenever output queues fall below the low-water mark. ! 155: To enable this mode the FASYNC flag should be set using ! 156: .IR fcntl (2). ! 157: .LP ! 158: .B "Input editing." ! 159: .LP ! 160: A UNIX terminal ordinarily operates in full-duplex mode. ! 161: Characters may be typed at any time, ! 162: even while output is occurring, and are only lost when the ! 163: system's character input buffers become completely ! 164: choked, which is rare, ! 165: or when the user has accumulated the maximum allowed number of ! 166: input characters that have not yet been read by some program. ! 167: Currently this limit is 256 characters. ! 168: In RAW mode, the terminal driver ! 169: throws away all input and output without notice when the limit is reached. ! 170: In CBREAK or cooked mode it refuses to accept any further input and, ! 171: if in the new line discipline, rings the terminal bell. ! 172: .PP ! 173: Input characters are normally accepted in either even or odd parity ! 174: with the parity bit being stripped off before the character is given to ! 175: the program. By clearing either the EVEN or ODD bit in the flags word ! 176: it is possible to have input characters with that parity discarded (see the ! 177: \fBSummary\fR below.) ! 178: .PP ! 179: In all of the line disciplines, it is possible to simulate terminal ! 180: input using the TIOCSTI ! 181: .IR ioctl , ! 182: which takes, as its third argument, ! 183: the address of a character. The system pretends that this character ! 184: was typed on the argument terminal, which must be the control terminal except ! 185: for the super-user (this call is not in standard version 7 UNIX). ! 186: .PP ! 187: Input characters are normally echoed by putting them in an output queue ! 188: as they arrive. This may be disabled by clearing the ECHO bit in the ! 189: flags word using the ! 190: .IR stty (3C) ! 191: call or the TIOCSETN or TIOCSETP ! 192: .IR ioctl s ! 193: (see the \fBSummary\fR below). ! 194: .PP ! 195: In cooked mode, terminal input is processed in units of lines. ! 196: A program attempting ! 197: to read will normally be suspended until an entire line has been ! 198: received ! 199: (but see the description of SIGTTIN in \fBJob access control\fR ! 200: and of FIONREAD in ! 201: \fBSummary\fR, both below.) ! 202: No matter how many characters are requested ! 203: in the read call, at most one line will be returned. ! 204: It is not, however, necessary to read a whole line at ! 205: once; any number of characters may be ! 206: requested in a read, even one, without losing information. ! 207: .PP ! 208: During input, line editing is normally done, with the erase character ! 209: .I sg_erase ! 210: (by default, DELETE) ! 211: logically erasing the last character typed and the ! 212: .I sg_kill ! 213: character (default, ^U: control-U) ! 214: logically erasing the entire current input line. ! 215: These characters ! 216: never erase beyond the beginning of the current input line or an eof. ! 217: These characters may be entered literally by ! 218: preceding them with `\e\|'; the `\e\|' will normally be erased when the ! 219: character is typed. ! 220: .PP ! 221: The drivers normally treat either a carriage return or a newline character ! 222: as terminating an input line, replacing the return with a newline and echoing ! 223: a return and a line feed. ! 224: If the CRMOD bit is cleared in the local mode word then the processing ! 225: for carriage return is disabled, and it is simply echoed as a return, ! 226: and does not terminate cooked mode input. ! 227: .PP ! 228: In the new driver there is a literal-next character (normally ^V) ! 229: which can be typed ! 230: in both cooked and CBREAK mode preceding ! 231: .I any ! 232: character to prevent its special meaning to the terminal handler. ! 233: This is to be preferred to the ! 234: use of `\e\|' escaping erase and kill characters, but `\e\|' is ! 235: retained with its old function in the new line discipline. ! 236: .PP ! 237: The new terminal driver also provides two other editing characters in ! 238: normal mode. The word-erase character, normally ^W, erases the preceding ! 239: word, but not any spaces before it. For the purposes of ^W, a word ! 240: is defined as a sequence of non-blank characters, with tabs counted as ! 241: blanks. ! 242: Finally, the reprint character, normally ^R, retypes the pending input beginning ! 243: on a new line. Retyping occurs automatically in cooked mode if characters ! 244: which would normally be erased from the screen are fouled by program output. ! 245: .LP ! 246: .B "Input echoing and redisplay" ! 247: .LP ! 248: The terminal driver has several modes (not present in standard UNIX ! 249: Version 7 systems) for handling the echoing of ! 250: terminal input, controlled by bits in a local mode word. ! 251: .LP ! 252: .I "Hardcopy terminals." ! 253: When a hardcopy terminal is in use, the LPRTERA bit is normally set in ! 254: the local mode word. Characters which are logically erased are ! 255: then printed out backwards preceded by `\e\|' and followed by `/' in this mode. ! 256: .LP ! 257: .I "CRT terminals." ! 258: When a CRT terminal is in use, the LCRTBS bit is normally set in the local ! 259: mode word. The terminal driver then echoes the proper number of erase ! 260: characters when input is erased; in the normal case where the erase ! 261: character is a ^H this causes the cursor of the terminal to back up ! 262: to where it was before the logically erased character was typed. ! 263: If the input has become fouled due to interspersed asynchronous output, ! 264: the input is automatically retyped. ! 265: .LP ! 266: .I "Erasing characters from a CRT." ! 267: When a CRT terminal is in use, the LCRTERA bit may be set to cause ! 268: input to be erased from the screen with a \*(lqbackspace-space-backspace\*(rq ! 269: sequence when character or word deleting sequences are used. ! 270: A LCRTKIL bit may be set as well, causing the input to ! 271: be erased in this manner on line kill sequences as well. ! 272: .LP ! 273: .I "Echoing of control characters." ! 274: If the LCTLECH bit is set in the local state word, then non-printing (control) ! 275: characters are normally echoed as ^X (for some X) ! 276: rather than being echoed unmodified; delete is echoed as ^?. ! 277: .LP ! 278: The normal modes for use on CRT terminals are speed dependent. ! 279: At speeds less than 1200 baud, the LCRTERA and LCRTKILL processing ! 280: is painfully slow, and ! 281: .IR stty (1) ! 282: normally just sets LCRTBS and LCTLECH; at ! 283: speeds of 1200 baud or greater all of these bits are normally set. ! 284: .IR Stty (1) ! 285: summarizes these option settings and the use of the new terminal ! 286: driver as ! 287: \*(lqnewcrt.\*(rq ! 288: .LP ! 289: .B "Output processing." ! 290: .PP ! 291: When one or more ! 292: characters are written, they are actually transmitted ! 293: to the terminal as soon as previously-written characters ! 294: have finished typing. ! 295: (As noted above, input characters are normally ! 296: echoed by putting them in the output queue ! 297: as they arrive.) ! 298: When a process produces characters more rapidly than they can be typed, ! 299: it will be suspended when its output queue exceeds some limit. ! 300: When the queue has drained down to some threshold ! 301: the program is resumed. ! 302: Even parity is normally generated on output. ! 303: The EOT character is not transmitted in cooked mode to prevent terminals ! 304: that respond to it from hanging up; programs using RAW or CBREAK mode ! 305: should be careful. ! 306: .PP ! 307: The terminal drivers provide necessary processing for cooked and CBREAK mode ! 308: output including delay generation for certain special characters and parity ! 309: generation. Delays are available after backspaces ^H, form feeds ^L, ! 310: carriage returns ^M, tabs ^I and newlines ^J. The driver will also optionally ! 311: expand tabs into spaces, where the tab stops are assumed to be set every ! 312: eight columns, and optionally convert newlines to carriage returns ! 313: followed by newline. These functions are controlled by bits in the tty ! 314: flags word; see \fBSummary\fR below. ! 315: .PP ! 316: The terminal drivers provide for mapping between upper and lower case ! 317: on terminals lacking lower case, and for other special processing on ! 318: deficient terminals. ! 319: .PP ! 320: Finally, in the new terminal driver, there is a output flush character, ! 321: normally ^O, which sets the LFLUSHO bit in the local mode word, causing ! 322: subsequent output to be flushed until it is cleared by a program or more ! 323: input is typed. This character has effect in both cooked and CBREAK modes ! 324: and causes pending input to be retyped if there is any pending input. ! 325: An ! 326: .I ioctl ! 327: to flush the characters in the input or output queues, TIOCFLUSH, ! 328: is also available. ! 329: .LP ! 330: .B "Upper case terminals and Hazeltines" ! 331: .PP ! 332: If the LCASE bit is set in the tty flags, then ! 333: all upper-case letters are mapped into ! 334: the corresponding lower-case letter. ! 335: The upper-case letter may be generated by preceding ! 336: it by `\\'. ! 337: Upper case letters are preceded by a `\e\|' when output. ! 338: In addition, the following escape sequences can be generated ! 339: on output and accepted on input: ! 340: .PP ! 341: .nf ! 342: for \` | ~ { } ! 343: use \e\|\' \e\|! \e\|^ \e\|( \e\|) ! 344: .fi ! 345: .PP ! 346: To deal with Hazeltine terminals, which do not understand that ~ has ! 347: been made into an ASCII character, the LTILDE bit may be set in the local ! 348: mode word; in this case the character ! 349: ~ will be replaced with the character \` on output. ! 350: .LP ! 351: .B "Flow control." ! 352: .PP ! 353: There are two characters (the stop character, normally ^S, and the ! 354: start character, normally ^Q) which cause output to be suspended and ! 355: resumed respectively. Extra stop characters typed when output ! 356: is already stopped have no effect, unless the start and stop characters ! 357: are made the same, in which case output resumes. ! 358: .PP ! 359: A bit in the flags word may be set to put the terminal into TANDEM mode. ! 360: In this mode the system produces a stop character (default ^S) when ! 361: the input queue is in danger of overflowing, and a start character (default ! 362: ^Q) when the input has drained sufficiently. This mode is useful ! 363: when the terminal is actually another machine that obeys those ! 364: conventions. ! 365: .LP ! 366: .B "Line control and breaks." ! 367: .LP ! 368: There are several ! 369: .I ioctl ! 370: calls available to control the state of the terminal line. ! 371: The TIOCSBRK ! 372: .I ioctl ! 373: will set the break bit in the hardware interface ! 374: causing a break condition to exist; this can be cleared (usually after a delay ! 375: with ! 376: .IR sleep (3)) ! 377: by TIOCCBRK. ! 378: Break conditions in the input are reflected as a null character in RAW mode ! 379: or as the interrupt character in cooked or CBREAK mode. ! 380: The TIOCCDTR ! 381: .I ioctl ! 382: will clear the data terminal ready condition; it can ! 383: be set again by TIOCSDTR. ! 384: .PP ! 385: When the carrier signal from the dataset drops (usually ! 386: because the user has hung up his terminal) a ! 387: SIGHUP hangup signal is sent to the processes in the distinguished ! 388: process group of the terminal; this usually causes them to terminate. ! 389: The SIGHUP can be suppressed by setting the LNOHANG bit in the local ! 390: state word of the driver. ! 391: Access to the terminal by other processes is then normally revoked, ! 392: so any further reads will fail, and programs that read a terminal and test for ! 393: end-of-file on their input will terminate appropriately. ! 394: .PP ! 395: It is possible to ask that the phone line be hung up on the last close ! 396: with the TIOCHPCL ! 397: .IR ioctl ; ! 398: this is normally done on the outgoing lines and dialups. ! 399: .LP ! 400: .B "Interrupt characters." ! 401: .PP ! 402: There are several characters that generate interrupts in cooked and CBREAK ! 403: mode; all are sent to the processes in the control group of the terminal, ! 404: as if a TIOCGPGRP ! 405: .I ioctl ! 406: were done to get the process group and then a ! 407: .IR killpg (2) ! 408: system call were done, ! 409: except that these characters also flush pending input and output when ! 410: typed at a terminal ! 411: (\fI\z'a\`'la\fR TIOCFLUSH). ! 412: The characters shown here are the defaults; the field names in the structures ! 413: (given below) ! 414: are also shown. ! 415: The characters may be changed. ! 416: .IP ^C ! 417: \fBt_intrc\fR (ETX) generates a SIGINT signal. ! 418: This is the normal way to stop a process which is no longer interesting, ! 419: or to regain control in an interactive program. ! 420: .IP ^\e ! 421: \fBt_quitc\fR (FS) generates a SIGQUIT signal. ! 422: This is used to cause a program to terminate and produce a core image, ! 423: if possible, ! 424: in the file ! 425: .B core ! 426: in the current directory. ! 427: .IP ^Z ! 428: \fBt_suspc\fR (EM) generates a SIGTSTP signal, which is used to suspend ! 429: the current process group. ! 430: .IP ^Y ! 431: \fBt_dsuspc\fR (SUB) generates a SIGTSTP signal as ^Z does, but the ! 432: signal is sent when a program attempts to read the ^Y, rather than when ! 433: it is typed. ! 434: .LP ! 435: .B "Job access control." ! 436: .PP ! 437: When using the new terminal driver, ! 438: if a process which is not in the distinguished process group of its ! 439: control terminal attempts to read from that terminal its process group is ! 440: sent a SIGTTIN signal. This signal normally causes the members of ! 441: that process group to stop. ! 442: If, however, the process is ignoring SIGTTIN, has SIGTTIN blocked, ! 443: or is in the middle of process creation using ! 444: .IR vfork (2)), ! 445: the read will return \-1 and set ! 446: .I errno ! 447: to EIO. ! 448: .PP ! 449: When using the new terminal driver with the LTOSTOP bit set in the local ! 450: modes, a process is prohibited from writing on its control terminal if it is ! 451: not in the distinguished process group for that terminal. ! 452: Processes which are holding or ignoring SIGTTOU signals ! 453: or which are in the middle of a ! 454: .IR vfork (2) ! 455: are excepted and allowed to produce output. ! 456: .LP ! 457: .B "Terminal/window sizes." ! 458: .LP ! 459: In order to accommodate terminals and workstations with variable-sized ! 460: windows, the terminal driver provides a mechanism for obtaining and setting ! 461: the current terminal size. ! 462: The driver does not use this information internally, but only stores it ! 463: and provides a uniform access mechanism. ! 464: When the size is changed, a SIGWINCH signal is sent to the terminal's process ! 465: group so that knowledgeable programs may detect size changes. ! 466: This facility was added in 4.3BSD and is not available in earlier ! 467: versions of the system. ! 468: .LP ! 469: .B "Summary of modes." ! 470: .LP ! 471: Unfortunately, due to the evolution of the terminal driver, ! 472: there are 4 different structures which contain various portions of the ! 473: driver data. The first of these (\fBsgttyb\fR) ! 474: contains that part of the information ! 475: largely common between version 6 and version 7 UNIX systems. ! 476: The second contains additional control characters added in version 7. ! 477: The third is a word of local state added in 4BSD, ! 478: and the fourth is another structure of special characters added for the ! 479: new driver. In the future a single structure may be made available ! 480: to programs which need to access all this information; most programs ! 481: need not concern themselves with all this state. ! 482: .de Ul ! 483: .ie t \\$1\l'|0\(ul' ! 484: .el \fI\\$1\fP ! 485: .. ! 486: .LP ! 487: .Ul "Basic modes: sgtty." ! 488: .PP ! 489: The basic ! 490: .IR ioctl s ! 491: use the structure ! 492: defined in ! 493: .IR <sgtty.h> : ! 494: .PP ! 495: .ta .5i 1i ! 496: .nf ! 497: .ft 3 ! 498: struct sgttyb { ! 499: char sg_ispeed; ! 500: char sg_ospeed; ! 501: char sg_erase; ! 502: char sg_kill; ! 503: short sg_flags; ! 504: }; ! 505: .ft R ! 506: .fi ! 507: .PP ! 508: The ! 509: .I sg_ispeed ! 510: and ! 511: .I sg_ospeed ! 512: fields describe the input and output speeds of the ! 513: device according to the following table, ! 514: which corresponds to the DEC DH-11 interface. ! 515: If other hardware is used, ! 516: impossible speed changes are ignored. ! 517: Symbolic values in the table are as defined in ! 518: .IR <sgtty.h> . ! 519: .PP ! 520: .nf ! 521: .ta \w'B9600 'u +5n ! 522: B0 0 (hang up dataphone) ! 523: B50 1 50 baud ! 524: B75 2 75 baud ! 525: B110 3 110 baud ! 526: B134 4 134.5 baud ! 527: B150 5 150 baud ! 528: B200 6 200 baud ! 529: B300 7 300 baud ! 530: B600 8 600 baud ! 531: B1200 9 1200 baud ! 532: B1800 10 1800 baud ! 533: B2400 11 2400 baud ! 534: B4800 12 4800 baud ! 535: B9600 13 9600 baud ! 536: EXTA 14 External A ! 537: EXTB 15 External B ! 538: .fi ! 539: .DT ! 540: .PP ! 541: Code conversion and line control required for ! 542: IBM 2741's (134.5 baud) ! 543: must be implemented by the user's ! 544: program. ! 545: The half-duplex line discipline ! 546: required for the 202 dataset (1200 baud) ! 547: is not supplied; full-duplex 212 datasets work fine. ! 548: .PP ! 549: The ! 550: .I sg_erase ! 551: and ! 552: .I sg_kill ! 553: fields of the argument structure ! 554: specify the erase and kill characters respectively. ! 555: (Defaults are DELETE and ^U.) ! 556: .PP ! 557: The ! 558: .I sg_flags ! 559: field of the argument structure ! 560: contains several bits that determine the ! 561: system's treatment of the terminal: ! 562: .PP ! 563: .ta \w'ALLDELAY 'u +\w'0100000 'u ! 564: .nf ! 565: ALLDELAY 0177400 Delay algorithm selection ! 566: BSDELAY 0100000 Select backspace delays (not implemented): ! 567: BS0 0 ! 568: BS1 0100000 ! 569: VTDELAY 0040000 Select form-feed and vertical-tab delays: ! 570: FF0 0 ! 571: FF1 0040000 ! 572: CRDELAY 0030000 Select carriage-return delays: ! 573: CR0 0 ! 574: CR1 0010000 ! 575: CR2 0020000 ! 576: CR3 0030000 ! 577: TBDELAY 0006000 Select tab delays: ! 578: TAB0 0 ! 579: TAB1 0002000 ! 580: TAB2 0004000 ! 581: XTABS 0006000 ! 582: NLDELAY 0001400 Select new-line delays: ! 583: NL0 0 ! 584: NL1 0000400 ! 585: NL2 0001000 ! 586: NL3 0001400 ! 587: EVENP 0000200 Even parity allowed on input ! 588: ODDP 0000100 Odd parity allowed on input ! 589: RAW 0000040 Raw mode: wake up on all characters, 8-bit interface ! 590: CRMOD 0000020 Map CR into LF; output LF as CR-LF ! 591: ECHO 0000010 Echo (full duplex) ! 592: LCASE 0000004 Map upper case to lower on input and lower to upper on output ! 593: CBREAK 0000002 Return each character as soon as typed ! 594: TANDEM 0000001 Automatic flow control ! 595: .DT ! 596: .fi ! 597: .PP ! 598: The delay bits specify how long ! 599: transmission stops to allow for mechanical or other movement ! 600: when certain characters are sent to the terminal. ! 601: In all cases a value of 0 indicates no delay. ! 602: .PP ! 603: Backspace delays are currently ignored but might ! 604: be used for Terminet 300's. ! 605: .PP ! 606: If a form-feed/vertical tab delay is specified, ! 607: it lasts for about 2 seconds. ! 608: .PP ! 609: Carriage-return delay type 1 lasts about .08 seconds ! 610: and is suitable for the Terminet 300. ! 611: Delay type 2 lasts about .16 seconds and is suitable ! 612: for the VT05 and the TI 700. ! 613: Delay type 3 is suitable for the concept-100 and pads lines ! 614: to be at least 9 characters at 9600 baud. ! 615: .PP ! 616: New-line delay type 1 is dependent on the current column ! 617: and is tuned for Teletype model 37's. ! 618: Type 2 is useful for the VT05 and is about .10 seconds. ! 619: Type 3 is unimplemented and is 0. ! 620: .PP ! 621: Tab delay type 1 is dependent on the amount of movement ! 622: and is tuned to the Teletype model ! 623: 37. ! 624: Type 3, called XTABS, ! 625: is not a delay at all but causes tabs to be replaced ! 626: by the appropriate number of spaces on output. ! 627: .PP ! 628: The flags for even and odd parity control parity checking on input ! 629: and generation on output in cooked and CBREAK mode ! 630: (unless LPASS8 is enabled, see below). ! 631: Even parity is generated on output unless ODDP is set and EVENP ! 632: is clear, in which case odd parity is generated. ! 633: Input characters with the wrong parity, as determined by EVENP and ! 634: ODDP, are ignored in cooked and CBREAK mode. ! 635: .PP ! 636: RAW ! 637: disables all processing save output flushing with LFLUSHO; ! 638: full 8 bits of input are given as soon as ! 639: it is available; all 8 bits are passed on output. ! 640: A break condition in the input is reported as a null character. ! 641: If the input queue overflows in raw mode all data in the input and output ! 642: queues are discarded; this applies to both new and old drivers. ! 643: .PP ! 644: CRMOD causes input carriage returns to be turned into ! 645: new-lines, and output and echoed new-lines to be output as a carriage return ! 646: followed by a line feed. ! 647: .PP ! 648: CBREAK is a sort of half-cooked (rare?) mode. ! 649: Programs can read each character as soon as typed, instead ! 650: of waiting for a full line; ! 651: all processing is done except the input editing: ! 652: character and word erase and line kill, input reprint, ! 653: and the special treatment of \e and EOT are disabled. ! 654: .PP ! 655: TANDEM mode causes the system to produce ! 656: a stop character (default ^S) whenever the input ! 657: queue is in danger of overflowing, and a start character ! 658: (default ^Q) ! 659: when the input queue has drained sufficiently. ! 660: It is useful for flow control when the `terminal' ! 661: is really another computer which understands the conventions. ! 662: .LP ! 663: .B Note: ! 664: The same ``stop'' and ``start'' characters are used for both directions ! 665: of flow control; the ! 666: .I t_stopc ! 667: character is accepted on input as the character that stops output and is ! 668: produced on output as the character to stop input, and the ! 669: .I t_startc ! 670: character is accepted on input as the character that restarts output and is ! 671: produced on output as the character to restart input. ! 672: .LP ! 673: .Ul "Basic ioctls" ! 674: .PP ! 675: A large number of ! 676: .IR ioctl (2) ! 677: calls apply to terminals. Some have the general form: ! 678: .PP ! 679: .B #include <sgtty.h> ! 680: .PP ! 681: .B ioctl(fildes, code, arg) ! 682: .br ! 683: .B struct sgttyb *arg; ! 684: .PP ! 685: The applicable codes are: ! 686: .IP TIOCGETP 15 ! 687: Fetch the basic parameters associated with the terminal, and store ! 688: in the pointed-to \fIsgttyb\fR structure. ! 689: .IP TIOCSETP ! 690: Set the parameters according to the pointed-to \fIsgttyb\fR structure. ! 691: The interface delays until output is quiescent, ! 692: then throws away any unread characters, ! 693: before changing the modes. ! 694: .IP TIOCSETN ! 695: Set the parameters like TIOCSETP but do not delay or flush input. ! 696: Input is not preserved, however, when changing to or from RAW. ! 697: .PP ! 698: With the following codes ! 699: .I arg ! 700: is ignored. ! 701: .IP TIOCEXCL 15 ! 702: Set \*(lqexclusive-use\*(rq mode: ! 703: no further opens are permitted until the file has been closed. ! 704: .IP TIOCNXCL ! 705: Turn off \*(lqexclusive-use\*(rq mode. ! 706: .IP TIOCHPCL ! 707: When the file is closed for the last time, ! 708: hang up the terminal. ! 709: This is useful when the line is associated ! 710: with an ACU used to place outgoing calls. ! 711: .PP ! 712: With the following codes ! 713: .I arg ! 714: is a pointer to an ! 715: .BR int . ! 716: .IP TIOCGETD 15 ! 717: .I arg ! 718: is a pointer to an ! 719: .B int ! 720: into which is placed the current line discipline number. ! 721: .IP TIOCSETD ! 722: .I arg ! 723: is a pointer to an ! 724: .B int ! 725: whose value becomes the current line discipline number. ! 726: .IP TIOCFLUSH ! 727: If the ! 728: .B int ! 729: pointed to by ! 730: .I arg ! 731: has a zero value, all characters waiting in input or output queues are flushed. ! 732: Otherwise, the value of the ! 733: .B int ! 734: is for the FREAD and FWRITE bits defined in ! 735: .BR <sys/file.h> ; ! 736: if the FREAD bit is set, all characters waiting in input queues are flushed, ! 737: and if the FWRITE bit is set, all characters waiting in output queues are ! 738: flushed. ! 739: .LP ! 740: The remaining calls are not available in vanilla version 7 UNIX. ! 741: In cases where arguments are required, they are described; \fIarg\fR ! 742: should otherwise be given as 0. ! 743: .IP TIOCSTI 15 ! 744: the argument points to a character which the system ! 745: pretends had been typed on the terminal. ! 746: .IP TIOCSBRK 15 ! 747: the break bit is set in the terminal. ! 748: .IP TIOCCBRK ! 749: the break bit is cleared. ! 750: .IP TIOCSDTR ! 751: data terminal ready is set. ! 752: .IP TIOCCDTR ! 753: data terminal ready is cleared. ! 754: .IP TIOCSTOP 15 ! 755: output is stopped as if the ``stop'' character had been typed. ! 756: .IP TIOCSTART ! 757: output is restarted as if the ``start'' character had been typed. ! 758: .IP TIOCGPGRP ! 759: .I arg ! 760: is a pointer to an ! 761: .B int ! 762: into which is placed the process group ID of the process group ! 763: for which this terminal is the control terminal. ! 764: .IP TIOCSPGRP ! 765: .I arg ! 766: is a pointer to an ! 767: .B int ! 768: which is the value to which the process group ID ! 769: for this terminal will be set. ! 770: .IP TIOCOUTQ ! 771: returns in the ! 772: .B int ! 773: pointed to by ! 774: .I arg ! 775: the number of characters queued for output to the terminal. ! 776: .IP FIONREAD ! 777: returns in the ! 778: .B int ! 779: pointed to by ! 780: .I arg ! 781: the number of characters immediately readable from the argument descriptor. ! 782: This works for files, pipes, and terminals. ! 783: .PP ! 784: .Ul Tchars ! 785: .PP ! 786: The second structure associated with each terminal specifies ! 787: characters that are special in both the old and new terminal interfaces: ! 788: The following structure is defined in ! 789: .IR <sys/ioctl.h> , ! 790: which is automatically included in ! 791: .IR <sgtty.h> : ! 792: .PP ! 793: .nf ! 794: .ft 3 ! 795: .ta .5i 1i 2i ! 796: struct tchars { ! 797: char t_intrc; /* interrupt */ ! 798: char t_quitc; /* quit */ ! 799: char t_startc; /* start output */ ! 800: char t_stopc; /* stop output */ ! 801: char t_eofc; /* end-of-file */ ! 802: char t_brkc; /* input delimiter (like nl) */ ! 803: }; ! 804: .DT ! 805: .fi ! 806: .ft R ! 807: .PP ! 808: The default values for these characters are ! 809: ^C, ^\e\|, ^Q, ^S, ^D, and \-1. ! 810: A character value of \-1 ! 811: eliminates the effect of that character. ! 812: The ! 813: .I t_brkc ! 814: character, by default \-1, ! 815: acts like a new-line in that it terminates a `line,' ! 816: is echoed, and is passed to the program. ! 817: The `stop' and `start' characters may be the same, ! 818: to produce a toggle effect. ! 819: It is probably counterproductive to make ! 820: other special characters (including erase and kill) ! 821: identical. ! 822: The applicable ! 823: .I ioctl ! 824: calls are: ! 825: .IP TIOCGETC 12 ! 826: Get the special characters and put them in the specified structure. ! 827: .IP TIOCSETC 12 ! 828: Set the special characters to those given in the structure. ! 829: .LP ! 830: .Ul "Local mode" ! 831: .PP ! 832: The third structure associated with each terminal is a local mode word. ! 833: The bits of the local mode word are: ! 834: .sp ! 835: .nf ! 836: LCRTBS 000001 Backspace on erase rather than echoing erase ! 837: LPRTERA 000002 Printing terminal erase mode ! 838: LCRTERA 000004 Erase character echoes as backspace-space-backspace ! 839: LTILDE 000010 Convert ~ to \` on output (for Hazeltine terminals) ! 840: LMDMBUF 000020 Stop/start output when carrier drops ! 841: LLITOUT 000040 Suppress output translations ! 842: LTOSTOP 000100 Send SIGTTOU for background output ! 843: LFLUSHO 000200 Output is being flushed ! 844: LNOHANG 000400 Don't send hangup when carrier drops ! 845: LETXACK 001000 Diablo style buffer hacking (unimplemented) ! 846: LCRTKIL 002000 BS-space-BS erase entire line on line kill ! 847: LPASS8 004000 Pass all 8 bits through on input, in any mode ! 848: LCTLECH 010000 Echo input control chars as ^X, delete as ^? ! 849: LPENDIN 020000 Retype pending input at next read or input character ! 850: LDECCTQ 040000 Only ^Q restarts output after ^S, like DEC systems ! 851: LNOFLSH 100000 Inhibit flushing of pending I/O when an interrupt character is typed. ! 852: .fi ! 853: .sp ! 854: The applicable ! 855: .I ioctl ! 856: functions are: ! 857: .IP TIOCLBIS 15 ! 858: .I arg ! 859: is a pointer to an ! 860: .B int ! 861: whose value is a mask containing the bits to be set in the local mode word. ! 862: .IP TIOCLBIC ! 863: .I arg ! 864: is a pointer to an ! 865: .B int ! 866: whose value is a mask containing the bits to be cleared in the local mode word. ! 867: .IP TIOCLSET ! 868: .I arg ! 869: is a pointer to an ! 870: .B int ! 871: whose value is stored in the local mode word. ! 872: .IP TIOCLGET ! 873: .I arg ! 874: is a pointer to an ! 875: .B int ! 876: into which the current local mode word is placed. ! 877: .LP ! 878: .Ul "Local special chars" ! 879: .PP ! 880: The ! 881: final control structure associated with each terminal is the ! 882: .I ltchars ! 883: structure which defines control characters ! 884: for the new terminal driver. ! 885: Its structure is: ! 886: .nf ! 887: .sp ! 888: .ta .5i 1i 2i ! 889: .ft B ! 890: struct ltchars { ! 891: char t_suspc; /* stop process signal */ ! 892: char t_dsuspc; /* delayed stop process signal */ ! 893: char t_rprntc; /* reprint line */ ! 894: char t_flushc; /* flush output (toggles) */ ! 895: char t_werasc; /* word erase */ ! 896: char t_lnextc; /* literal next character */ ! 897: }; ! 898: .ft R ! 899: .fi ! 900: .sp ! 901: The default values for these characters are ^Z, ^Y, ^R, ^O, ^W, and ^V. ! 902: A value of \-1 disables the character. ! 903: .PP ! 904: The applicable \fIioctl\fR functions are: ! 905: .IP TIOCSLTC 12 ! 906: .I arg ! 907: is a pointer to an ! 908: .I ltchars ! 909: structure which defines the new local special characters. ! 910: .IP TIOCGLTC 12 ! 911: .I arg ! 912: is a pointer to an ! 913: .I ltchars ! 914: structure into which is placed the current set of local special characters. ! 915: .LP ! 916: .Ul "Window/terminal sizes" ! 917: .PP ! 918: Each terminal has provision for storage of the current terminal or window ! 919: size in a ! 920: .I winsize ! 921: structure, with format: ! 922: .nf ! 923: .sp ! 924: .ft B ! 925: .ta .5i +\w'unsigned short\ \ \ \ 'u +\w'ws_ypixel;\ \ \ \ \ 'u ! 926: struct winsize { ! 927: unsigned short ws_row; /* rows, in characters */ ! 928: unsigned short ws_col; /* columns, in characters */ ! 929: unsigned short ws_xpixel; /* horizontal size, pixels */ ! 930: unsigned short ws_ypixel; /* vertical size, pixels */ ! 931: }; ! 932: .ft R ! 933: .fi ! 934: .LP ! 935: A value of 0 in any field is interpreted as ``undefined;'' ! 936: the entire structure is zeroed on final close. ! 937: .PP ! 938: The applicable \fIioctl\fP functions are: ! 939: .IP TIOCGWINSZ ! 940: .I arg ! 941: is a pointer to a ! 942: .B "struct winsize" ! 943: into which will be placed the current terminal or window size information. ! 944: .IP TIOCSWINSZ ! 945: .I arg ! 946: is a pointer to a ! 947: .B "struct winsize" ! 948: which will be used to set the current terminal or window size information. ! 949: If the new information is different than the old information, ! 950: a SIGWINCH signal will be sent to the terminal's process group. ! 951: .SH FILES ! 952: /dev/tty ! 953: .br ! 954: /dev/tty* ! 955: .br ! 956: /dev/console ! 957: .SH SEE ALSO ! 958: csh(1), ! 959: stty(1), ! 960: tset(1), ! 961: ioctl(2), ! 962: sigvec(2), ! 963: stty(3C), ! 964: getty(8)
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