unlocked_stdio

UNLOCKED_STDIO(3)          Linux Programmer's Manual         UNLOCKED_STDIO(3)

NAME
       getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked - non-
       locking stdio functions

SYNOPSIS
       #include <stdio.h>

       int getc_unlocked(FILE *stream);
       int getchar_unlocked(void);
       int putc_unlocked(int c, FILE *stream);
       int putchar_unlocked(int c);

       void clearerr_unlocked(FILE *stream);
       int feof_unlocked(FILE *stream);
       int ferror_unlocked(FILE *stream);
       int fileno_unlocked(FILE *stream);
       int fflush_unlocked(FILE *stream);
       int fgetc_unlocked(FILE *stream);
       int fputc_unlocked(int c, FILE *stream);
       size_t fread_unlocked(void *ptr, size_t size, size_t n,
                             FILE *stream);
       size_t fwrite_unlocked(const void *ptr, size_t size, size_t n,
                             FILE *stream);

       char *fgets_unlocked(char *s, int n, FILE *stream);
       int fputs_unlocked(const char *s, FILE *stream);

       #include <wchar.h>

       wint_t getwc_unlocked(FILE *stream);
       wint_t getwchar_unlocked(void);
       wint_t fgetwc_unlocked(FILE *stream);
       wint_t fputwc_unlocked(wchar_t wc, FILE *stream);
       wint_t putwc_unlocked(wchar_t wc, FILE *stream);
       wint_t putwchar_unlocked(wchar_t wc);
       wchar_t *fgetws_unlocked(wchar_t *ws, int n, FILE *stream);
       int fputws_unlocked(const wchar_t *ws, FILE *stream);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getc_unlocked(), getchar_unlocked(), putc_unlocked(), putchar_un-
       locked():
           /* Since glibc 2.24: */ _POSIX_C_SOURCE >= 199309L
               || /* Glibc versions <= 2.23: */ _POSIX_C_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

       clearerr_unlocked(), feof_unlocked(), ferror_unlocked(), fileno_un-
       locked(), fflush_unlocked(), fgetc_unlocked(), fputc_unlocked(),
       fread_unlocked(), fwrite_unlocked():
           /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

       fgets_unlocked(), fputs_unlocked(), getwc_unlocked(), getwchar_un-
       locked(), fgetwc_unlocked(), fputwc_unlocked(), putwchar_unlocked(),
       fgetws_unlocked(), fputws_unlocked():
           _GNU_SOURCE

DESCRIPTION
       Each  of these functions has the same behavior as its counterpart with-
       out the "_unlocked" suffix, except that they do not use  locking  (they
       do  not set locks themselves, and do not test for the presence of locks
       set by others) and hence are thread-unsafe.  See flockfile(3).

ATTRIBUTES
       For an  explanation  of  the  terms  used  in  this  section,  see  at-
       tributes(7).

       +---------------------+---------------+-----------------------+
       |Interface            | Attribute     | Value                 |
       +---------------------+---------------+-----------------------+
       |getc_unlocked(),     | Thread safety | MT-Safe race:stream   |
       |putc_unlocked(),     |               |                       |
       |clearerr_unlocked(), |               |                       |
       |fflush_unlocked(),   |               |                       |
       |fgetc_unlocked(),    |               |                       |
       |fputc_unlocked(),    |               |                       |
       |fread_unlocked(),    |               |                       |
       |fwrite_unlocked(),   |               |                       |
       |fgets_unlocked(),    |               |                       |
       |fputs_unlocked(),    |               |                       |
       |getwc_unlocked(),    |               |                       |
       |fgetwc_unlocked(),   |               |                       |
       |fputwc_unlocked(),   |               |                       |
       |putwc_unlocked(),    |               |                       |
       |fgetws_unlocked(),   |               |                       |
       |fputws_unlocked()    |               |                       |
       +---------------------+---------------+-----------------------+
       |getchar_unlocked(),  | Thread safety | MT-Unsafe race:stdin  |
       |getwchar_unlocked()  |               |                       |
       +---------------------+---------------+-----------------------+
       |putchar_unlocked(),  | Thread safety | MT-Unsafe race:stdout |
       |putwchar_unlocked()  |               |                       |
       +---------------------+---------------+-----------------------+
       |feof_unlocked(),     | Thread safety | MT-Safe               |
       |ferror_unlocked(),   |               |                       |
       |fileno_unlocked()    |               |                       |
       +---------------------+---------------+-----------------------+
CONFORMING TO
       The  four  functions  getc_unlocked(),   getchar_unlocked(),   putc_un-
       locked(), putchar_unlocked() are in POSIX.1-2001 and POSIX.1-2008.

       The  nonstandard *_unlocked() variants occur on a few UNIX systems, and
       are available in recent glibc.  They should probably not be used.

SEE ALSO
       flockfile(3), stdio(3)

COLOPHON
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       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

                                  2017-09-15                 UNLOCKED_STDIO(3)
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