Return to scanf.3 CVS log

Up to [Research Unix] / researchv10dc / man / man3

Annotation of researchv10dc/man/man3/scanf.3, revision 1.1

1.1     ! root        1: .TH SCANF 3S
        !             2: .CT 2 file_io data_man
        !             3: .SH NAME
        !             4: scanf, fscanf, sscanf \(mi formatted input
        !             5: .SH SYNOPSIS
        !             6: .nf
        !             7: .B #include <stdio.h>
        !             8: .PP
        !             9: .B
        !            10: scanf(format [ , pointer ] ... )
        !            11: .B char *format;
        !            12: .PP
        !            13: .B
        !            14: fscanf(stream, format [ , pointer ] ... )
        !            15: .B FILE *stream;
        !            16: .B char *format;
        !            17: .PP
        !            18: .B
        !            19: sscanf(s, format [ , pointer ] ... )
        !            20: .B char *s, *format;
        !            21: .fi
        !            22: .SH DESCRIPTION
        !            23: .I Scanf
        !            24: reads from the standard input stream
        !            25: .IR stdin .
        !            26: .I Fscanf
        !            27: reads from the named input
        !            28: .IR stream .
        !            29: .I Sscanf
        !            30: reads from the character string
        !            31: .IR s .
        !            32: Each function reads characters, interprets
        !            33: them according to a format, and stores the results in its arguments.
        !            34: Each expects as arguments
        !            35: a control string
        !            36: .I format,
        !            37: described below,
        !            38: and a set of
        !            39: arguments, normally pointers,
        !            40: indicating where the converted input should be stored.
        !            41: .PP
        !            42: The
        !            43: control string
        !            44: usually contains
        !            45: conversion specifications, which are used to direct interpretation
        !            46: of input sequences.
        !            47: The control string may contain:
        !            48: .TP 4
        !            49: 1.
        !            50: Blanks, tabs or newlines,
        !            51: which match optional white space in the input.
        !            52: .TP 4
        !            53: 2.
        !            54: An ordinary character (not
        !            55: .LR % )
        !            56: which must match
        !            57: the next character of the input stream.
        !            58: .TP 4
        !            59: 3.
        !            60: Conversion specifications, consisting of the
        !            61: character
        !            62: .BR % ,
        !            63: an optional assignment suppressing character
        !            64: .BR * ,
        !            65: an optional numerical maximum field width, and a conversion
        !            66: character.
        !            67: .PP
        !            68: A conversion specification directs the conversion of the
        !            69: next input field; the result
        !            70: is placed in the variable pointed to by the corresponding argument,
        !            71: unless assignment suppression was
        !            72: indicated by
        !            73: .BR * .
        !            74: Conversions other than
        !            75: .L c
        !            76: and
        !            77: .L [
        !            78: skip white space and consume
        !            79: non-white-space characters up
        !            80: to the next inappropriate character or until the field
        !            81: width, if specified, is exhausted.
        !            82: The field width is either an integer constant or
        !            83: .LR ! .
        !            84: In the latter case, the width is taken from an integer argument
        !            85: that precedes the next pointer argument.
        !            86: .PP
        !            87: The conversion character indicates the interpretation of the
        !            88: input field; the corresponding pointer argument must
        !            89: usually be of a restricted type.
        !            90: The following conversion characters are legal:
        !            91: .TP 4
        !            92: .B  %
        !            93: A single 
        !            94: .L %
        !            95: is expected
        !            96: in the input at this point;
        !            97: no assignment is done.
        !            98: .TP 4
        !            99: .B  d
        !           100: A decimal integer is expected;
        !           101: the corresponding argument should be an integer pointer.
        !           102: .TP 4
        !           103: .B  o
        !           104: an octal integer is expected;
        !           105: the corresponding argument should be an integer pointer.
        !           106: .TP 4
        !           107: .B  x
        !           108: A hexadecimal integer is expected;
        !           109: the corresponding argument should be an integer pointer.
        !           110: .ti -0.2i
        !           111: .TP 4
        !           112: .B  s
        !           113: A character string is expected;
        !           114: the corresponding argument should be a character pointer
        !           115: pointing to an array of characters large enough to accept the
        !           116: string and a terminating
        !           117: .LR \e0 ,
        !           118: which will be added.
        !           119: The input field is terminated by a space character
        !           120: or a newline.
        !           121: .TP 4
        !           122: .B  c
        !           123: A character is expected; the
        !           124: corresponding argument should be a character pointer.
        !           125: If a field width is given, the corresponding argument
        !           126: should refer to a character array, and the
        !           127: indicated number of characters is read.
        !           128: .ne3
        !           129: .TP 4
        !           130: .B e
        !           131: .br
        !           132: .ns
        !           133: .TP
        !           134: f
        !           135: A
        !           136: floating point number is expected;
        !           137: the next field is converted accordingly and stored through the
        !           138: corresponding argument, which should be a pointer to a
        !           139: .IR float .
        !           140: The input format for
        !           141: floating point numbers is
        !           142: an optionally signed
        !           143: string of digits
        !           144: possibly containing a decimal point, followed by an optional
        !           145: exponent field consisting of an
        !           146: .B E
        !           147: or
        !           148: .B e
        !           149: followed by an optionally signed integer.
        !           150: .ne 3
        !           151: .TP 4
        !           152: .B  [
        !           153: .br
        !           154: .ns
        !           155: .TP
        !           156: .B [^
        !           157: A character string is expected.
        !           158: The left bracket (or bracket and circumflex)
        !           159: is followed by a set of characters and a right
        !           160: bracket.
        !           161: When the set is introduced by
        !           162: .B [
        !           163: (or
        !           164: .BR [^ ),
        !           165: the string consists only
        !           166: of characters in (or not in) the set.
        !           167: The corresponding argument must point to a character array.
        !           168: .PP
        !           169: The conversion characters
        !           170: .BR d ,
        !           171: .B o
        !           172: and
        !           173: .B x
        !           174: may be preceded by
        !           175: .B l
        !           176: to indicate that a pointer to
        !           177: .B long
        !           178: rather than to
        !           179: .B int
        !           180: is in the argument list.
        !           181: Similarly, the conversion characters
        !           182: .B e
        !           183: or
        !           184: .B f
        !           185: may be preceded by
        !           186: .B l
        !           187: to indicate a pointer to
        !           188: .B double
        !           189: rather than to
        !           190: .BR float .
        !           191: The conversion characters
        !           192: .BR d ,
        !           193: .B o
        !           194: and
        !           195: .B x
        !           196: may be preceded by
        !           197: .B h
        !           198: to indicate a pointer to
        !           199: .BR short .
        !           200: .PP
        !           201: The
        !           202: .I scanf
        !           203: functions return the number of successfully matched and assigned input
        !           204: items.
        !           205: This can be used to decide how many input items were found.
        !           206: The constant
        !           207: .SM
        !           208: .B EOF
        !           209: is returned upon end of input; note that this is different
        !           210: from
        !           211: .LR 0 ,
        !           212: which means that no conversion was done;
        !           213: if conversion was intended, it was frustrated by an
        !           214: inappropriate character in the input.
        !           215: .PP
        !           216: For example, the call
        !           217: .nf
        !           218: .ft L
        !           219:        int i; float x; char name[50];
        !           220:        scanf("%d%f%s", &i, &x, name);
        !           221: .fi
        !           222: .ft P
        !           223: .PP
        !           224: with the input line
        !           225: .IP
        !           226: .L
        !           227: 25   54.32E\(mi1  thompson
        !           228: .PP
        !           229: will assign to
        !           230: .I i
        !           231: the value
        !           232: .LR 25 ,
        !           233: .I x
        !           234: the value
        !           235: .LR 5.432 ,
        !           236: and
        !           237: .I name
        !           238: will contain
        !           239: .LR thompson\e0 .
        !           240: Or,
        !           241: .nf
        !           242: .ft L
        !           243:        int i; float x; char name[50];
        !           244:        scanf("%2d%f%*d%[1234567890]", &i, &x, name);
        !           245: .fi
        !           246: .ft P
        !           247: .PP
        !           248: with input
        !           249: .IP
        !           250: \fL56789 0123 56a72\fP
        !           251: .PP
        !           252: will assign
        !           253: .L 56
        !           254: to
        !           255: .IR i ,
        !           256: .L 789.0
        !           257: to
        !           258: .IR x ,
        !           259: skip
        !           260: .LR 0123 ,
        !           261: and place the string
        !           262: .L 56\e0
        !           263: in
        !           264: .IR name .
        !           265: The next call to
        !           266: .I getchar
        !           267: will return 
        !           268: .LR a .
        !           269: .SH "SEE ALSO"
        !           270: .IR atof (3),
        !           271: .IR stdio (3),
        !           272: .IR ungetc (3)
        !           273: .SH DIAGNOSTICS
        !           274: The
        !           275: .I scanf
        !           276: functions return
        !           277: .B EOF
        !           278: on end of input,
        !           279: and a short count for missing or illegal data items.
        !           280: .SH BUGS
        !           281: The success of literal matches and suppressed
        !           282: assignments is not directly
        !           283: determinable.
        !           284: .br
        !           285: The input scan stops short of the end of excessively
        !           286: long numbers.
        !           287: .br
        !           288: There is no
        !           289: .LR %# .
        !           290: .br
        !           291: When no maximum field width is given in a
        !           292: .L %s
        !           293: or
        !           294: .L %[]
        !           295: conversion specification, improper input can
        !           296: overrun the output string and corrupt the program in
        !           297: arbitrarily malicious ways.
        !           298: The best alternative,
        !           299: .LR %!s ,
        !           300: is nonstandard.
        !           301: .br
        !           302: A deprecated usage allows upper-case conversion characters
        !           303: as equivalents for lower-case characters preceded by
        !           304: .LR l .

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.