| 1 | .\" Copyright (c) 1980 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 | .\" @(#)stdio.3 6.2 (Berkeley) %G% |
| 6 | .\" |
| 7 | .TH STDIO 3S "" |
| 8 | .UC 4 |
| 9 | .SH NAME |
| 10 | stdio \- standard buffered input/output package |
| 11 | .SH SYNOPSIS |
| 12 | .B #include <stdio.h> |
| 13 | .PP |
| 14 | .SM |
| 15 | .B FILE |
| 16 | .B *stdin; |
| 17 | .br |
| 18 | .SM |
| 19 | .B FILE |
| 20 | .B *stdout; |
| 21 | .br |
| 22 | .SM |
| 23 | .B FILE |
| 24 | .B *stderr; |
| 25 | .SH DESCRIPTION |
| 26 | The functions described in section 3S constitute a user-level buffering |
| 27 | scheme. The in-line macros |
| 28 | .I getc |
| 29 | and |
| 30 | .IR putc (3S) |
| 31 | handle characters quickly. The higher level routines |
| 32 | .IR gets , |
| 33 | .IR fgets , |
| 34 | .IR scanf , |
| 35 | .IR fscanf , |
| 36 | .IR fread , |
| 37 | .IR puts , |
| 38 | .IR fputs , |
| 39 | .IR printf , |
| 40 | .IR fprintf , |
| 41 | .IR fwrite |
| 42 | all use |
| 43 | .I getc |
| 44 | and |
| 45 | .IR putc ; |
| 46 | they can be freely intermixed. |
| 47 | .PP |
| 48 | A file with associated buffering is called a |
| 49 | .IR stream , |
| 50 | and is declared to be a pointer to a defined type |
| 51 | .SM |
| 52 | .BR FILE . |
| 53 | .IR Fopen (3S) |
| 54 | creates certain descriptive data for a stream |
| 55 | and returns a pointer to designate the stream in all further transactions. |
| 56 | There are three normally open streams with constant pointers declared in |
| 57 | the include file and associated with the standard open files: |
| 58 | .TP 10n |
| 59 | .B stdin |
| 60 | standard input file |
| 61 | .br |
| 62 | .ns |
| 63 | .TP |
| 64 | .B stdout |
| 65 | standard output file |
| 66 | .br |
| 67 | .ns |
| 68 | .TP |
| 69 | .B stderr |
| 70 | standard error file |
| 71 | .PP |
| 72 | A constant `pointer' |
| 73 | .SM |
| 74 | .B NULL |
| 75 | (0) |
| 76 | designates no stream at all. |
| 77 | .PP |
| 78 | An integer constant |
| 79 | .SM |
| 80 | .B EOF |
| 81 | (\-1) is returned upon end of file or error by integer functions that |
| 82 | deal with streams. |
| 83 | .PP |
| 84 | Any routine that uses the standard input/output package |
| 85 | must include the header file |
| 86 | .RI < stdio.h > |
| 87 | of pertinent macro definitions. |
| 88 | The functions and constants mentioned in sections labeled 3S |
| 89 | are declared in the include file and need no further declaration. |
| 90 | The constants, and the following `functions' are |
| 91 | implemented as macros; redeclaration of these names is perilous: |
| 92 | .IR getc , |
| 93 | .IR getchar , |
| 94 | .IR putc , |
| 95 | .IR putchar , |
| 96 | .IR feof , |
| 97 | .IR ferror , |
| 98 | .IR fileno . |
| 99 | .SH "SEE ALSO" |
| 100 | open(2), close(2), read(2), write(2), fread(3S), fseek(3S), f*(3S) |
| 101 | .SH DIAGNOSTICS |
| 102 | The value |
| 103 | .SM |
| 104 | .B EOF |
| 105 | is returned uniformly to indicate that a |
| 106 | .SM |
| 107 | .B FILE |
| 108 | pointer has not been initialized with |
| 109 | .IR fopen , |
| 110 | input (output) has been attempted on an output (input) stream, or a |
| 111 | .SM |
| 112 | .B FILE |
| 113 | pointer designates corrupt or otherwise unintelligible |
| 114 | .SM |
| 115 | .B FILE |
| 116 | data. |
| 117 | .PP |
| 118 | For purposes of efficiency, this implementation of the standard library |
| 119 | has been changed to line buffer output to a terminal by default and attempts |
| 120 | to do this transparently by flushing the output whenever a |
| 121 | .IR read (2) |
| 122 | from the standard input is necessary. This is almost always transparent, |
| 123 | but may cause confusion or malfunctioning of programs which use |
| 124 | standard i/o routines but use |
| 125 | .IR read (2) |
| 126 | themselves to read from the standard input. |
| 127 | .PP |
| 128 | In cases where a large amount of computation is done after printing |
| 129 | part of a line on an output terminal, it is necessary to |
| 130 | .IR fflush (3S) |
| 131 | the standard output before going off and computing so that the output |
| 132 | will appear. |
| 133 | .SH BUGS |
| 134 | The standard buffered functions do not interact well with certain other |
| 135 | library and system functions, especially \fIvfork\fP and \fIabort\fP. |
| 136 | .SH "LIST OF FUNCTIONS" |
| 137 | .sp 2 |
| 138 | .nf |
| 139 | .ta \w'setlinebuf'u+2n +\w'setbuf.3s'u+10n |
| 140 | \fIName\fP \fIAppears on Page\fP \fIDescription\fP |
| 141 | .ta \w'setlinebuf'u+4n +\w'setbuf.3s'u+4n |
| 142 | .sp 5p |
| 143 | clearerr ferror.3s stream status inquiries |
| 144 | fclose fclose.3s close or flush a stream |
| 145 | fdopen fopen.3s open a stream |
| 146 | feof ferror.3s stream status inquiries |
| 147 | ferror ferror.3s stream status inquiries |
| 148 | fflush fclose.3s close or flush a stream |
| 149 | fgetc getc.3s get character or word from stream |
| 150 | fgets gets.3s get a string from a stream |
| 151 | fileno ferror.3s stream status inquiries |
| 152 | fopen fopen.3s open a stream |
| 153 | fprintf printf.3s formatted output conversion |
| 154 | fputc putc.3s put character or word on a stream |
| 155 | fputs puts.3s put a string on a stream |
| 156 | fread fread.3s buffered binary input/output |
| 157 | freopen fopen.3s open a stream |
| 158 | fscanf scanf.3s formatted input conversion |
| 159 | fseek fseek.3s reposition a stream |
| 160 | ftell fseek.3s reposition a stream |
| 161 | fwrite fread.3s buffered binary input/output |
| 162 | getc getc.3s get character or word from stream |
| 163 | getchar getc.3s get character or word from stream |
| 164 | gets gets.3s get a string from a stream |
| 165 | getw getc.3s get character or word from stream |
| 166 | printf printf.3s formatted output conversion |
| 167 | putc putc.3s put character or word on a stream |
| 168 | putchar putc.3s put character or word on a stream |
| 169 | puts puts.3s put a string on a stream |
| 170 | putw putc.3s put character or word on a stream |
| 171 | rewind fseek.3s reposition a stream |
| 172 | scanf scanf.3s formatted input conversion |
| 173 | setbuf setbuf.3s assign buffering to a stream |
| 174 | setbuffer setbuf.3s assign buffering to a stream |
| 175 | setlinebuf setbuf.3s assign buffering to a stream |
| 176 | sprintf printf.3s formatted output conversion |
| 177 | sscanf scanf.3s formatted input conversion |
| 178 | ungetc ungetc.3s push character back into input stream |
| 179 | .fi |