man3/unlocked_stdio.3

   1 .\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>.
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .TH UNLOCKED_STDIO 3 2021-03-22 GNU "Linux Programmer's Manual"
   6 .SH NAME
   7 getc_unlocked, getchar_unlocked, putc_unlocked,
   8 putchar_unlocked \- nonlocking stdio functions
   9 .SH LIBRARY
  10 Standard C library
  11 .RI ( libc ", " \-lc )
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <stdio.h>
  15 .PP
  16 .BI "int getc_unlocked(FILE *" stream );
  17 .B "int getchar_unlocked(void);"
  18 .BI "int putc_unlocked(int " c ", FILE *" stream );
  19 .BI "int putchar_unlocked(int " c );
  20 .PP
  21 .BI "void clearerr_unlocked(FILE *" stream );
  22 .BI "int feof_unlocked(FILE *" stream );
  23 .BI "int ferror_unlocked(FILE *" stream );
  24 .BI "int fileno_unlocked(FILE *" stream );
  25 .BI "int fflush_unlocked(FILE *" stream );
  26 .PP
  27 .BI "int fgetc_unlocked(FILE *" stream );
  28 .BI "int fputc_unlocked(int " c ", FILE *" stream );
  29 .PP
  30 .BI "size_t fread_unlocked(void *restrict " ptr ", size_t " size ", size_t " n ,
  31 .BI "                      FILE *restrict " stream );
  32 .BI "size_t fwrite_unlocked(const void *restrict " ptr ", size_t " size \
  33 ", size_t " n ,
  34 .BI "                      FILE *restrict " stream );
  35 .PP
  36 .BI "char *fgets_unlocked(char *restrict " s ", int " n \
  37 ", FILE *restrict " stream );
  38 .BI "int fputs_unlocked(const char *restrict " s ", FILE *restrict " stream );
  39 .PP
  40 .B #include <wchar.h>
  41 .PP
  42 .BI "wint_t getwc_unlocked(FILE *" stream );
  43 .B "wint_t getwchar_unlocked(void);"
  44 .BI "wint_t fgetwc_unlocked(FILE *" stream );
  45 .PP
  46 .BI "wint_t fputwc_unlocked(wchar_t " wc ", FILE *" stream );
  47 .BI "wint_t putwc_unlocked(wchar_t " wc ", FILE *" stream );
  48 .BI "wint_t putwchar_unlocked(wchar_t " wc );
  49 .PP
  50 .BI "wchar_t *fgetws_unlocked(wchar_t *restrict " ws ", int " n ,
  51 .BI "                      FILE *restrict " stream );
  52 .BI "int fputws_unlocked(const wchar_t *restrict " ws ,
  53 .BI "                      FILE *restrict " stream );
  54 .fi
  55 .PP
  56 .RS -4
  57 Feature Test Macro Requirements for glibc (see
  58 .BR feature_test_macros (7)):
  59 .nh
  60 .RE
  61 .ad l
  62 .PP
  63 .BR getc_unlocked (),
  64 .BR getchar_unlocked (),
  65 .BR putc_unlocked (),
  66 .BR putchar_unlocked ():
  67 .nf
  68     /* Since glibc 2.24: */ _POSIX_C_SOURCE >= 199309L
  69         || /* Glibc <= 2.23: */ _POSIX_C_SOURCE
  70         || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
  71 .fi
  72 .PP
  73 .BR clearerr_unlocked (),
  74 .BR feof_unlocked (),
  75 .BR ferror_unlocked (),
  76 .BR fileno_unlocked (),
  77 .BR fflush_unlocked (),
  78 .BR fgetc_unlocked (),
  79 .BR fputc_unlocked (),
  80 .BR fread_unlocked (),
  81 .BR fwrite_unlocked ():
  82 .nf
  83     /* Glibc since 2.19: */ _DEFAULT_SOURCE
  84         || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
  85 .fi
  86 .PP
  87 .BR fgets_unlocked (),
  88 .BR fputs_unlocked (),
  89 .BR getwc_unlocked (),
  90 .BR getwchar_unlocked (),
  91 .BR fgetwc_unlocked (),
  92 .BR fputwc_unlocked (),
  93 .BR putwchar_unlocked (),
  94 .BR fgetws_unlocked (),
  95 .BR fputws_unlocked ():
  96 .nf
  97     _GNU_SOURCE
  98 .fi
  99 .hy
 100 .ad
 101 .SH DESCRIPTION
 102 Each of these functions has the same behavior as its counterpart
 103 without the "_unlocked" suffix, except that they do not use locking
 104 (they do not set locks themselves, and do not test for the presence
 105 of locks set by others) and hence are thread-unsafe.
 106 See
 107 .BR flockfile (3).
 108 .SH ATTRIBUTES
 109 For an explanation of the terms used in this section, see
 110 .BR attributes (7).
 111 .ad l
 112 .nh
 113 .TS
 114 allbox;
 115 lb lb lbx
 116 l l l.
 117 Interface       Attribute       Value
 118 T{
 119 .BR getc_unlocked (),
 120 .BR putc_unlocked (),
 121 .BR clearerr_unlocked (),
 122 .BR fflush_unlocked (),
 123 .BR fgetc_unlocked (),
 124 .BR fputc_unlocked (),
 125 .BR fread_unlocked (),
 126 .BR fwrite_unlocked (),
 127 .BR fgets_unlocked (),
 128 .BR fputs_unlocked (),
 129 .BR getwc_unlocked (),
 130 .BR fgetwc_unlocked (),
 131 .BR fputwc_unlocked (),
 132 .BR putwc_unlocked (),
 133 .BR fgetws_unlocked (),
 134 .BR fputws_unlocked ()
 135 T}      Thread safety   T{
 136 MT-Safe race:stream
 137 T}
 138 T{
 139 .BR getchar_unlocked (),
 140 .BR getwchar_unlocked ()
 141 T}      Thread safety   T{
 142 MT-Unsafe race:stdin
 143 T}
 144 T{
 145 .BR putchar_unlocked (),
 146 .BR putwchar_unlocked ()
 147 T}      Thread safety   T{
 148 MT-Unsafe race:stdout
 149 T}
 150 T{
 151 .BR feof_unlocked (),
 152 .BR ferror_unlocked (),
 153 .BR fileno_unlocked ()
 154 T}      Thread safety   MT-Safe
 155 .TE
 156 .hy
 157 .ad
 158 .sp 1
 159 .SH CONFORMING TO
 160 The four functions
 161 .BR getc_unlocked (),
 162 .BR getchar_unlocked (),
 163 .BR putc_unlocked (),
 164 .BR putchar_unlocked ()
 165 are in POSIX.1-2001 and POSIX.1-2008.
 166 .PP
 167 The nonstandard
 168 .BR *_unlocked ()
 169 variants occur on a few UNIX systems, and are available in recent glibc.
 170 .\" E.g., in HP-UX 10.0. In HP-UX 10.30 they are called obsolescent, and
 171 .\" moved to a compatibility library.
 172 .\" Available in HP-UX 10.0: clearerr_unlocked, fclose_unlocked,
 173 .\" feof_unlocked, ferror_unlocked, fflush_unlocked, fgets_unlocked,
 174 .\" fgetwc_unlocked, fgetws_unlocked, fileno_unlocked, fputs_unlocked,
 175 .\" fputwc_unlocked, fputws_unlocked, fread_unlocked, fseek_unlocked,
 176 .\" ftell_unlocked, fwrite_unlocked, getc_unlocked, getchar_unlocked,
 177 .\" getw_unlocked, getwc_unlocked, getwchar_unlocked, putc_unlocked,
 178 .\" putchar_unlocked, puts_unlocked, putws_unlocked, putw_unlocked,
 179 .\" putwc_unlocked, putwchar_unlocked, rewind_unlocked, setvbuf_unlocked,
 180 .\" ungetc_unlocked, ungetwc_unlocked.
 181 They should probably not be used.
 182 .SH SEE ALSO
 183 .BR flockfile (3),
 184 .BR stdio (3)