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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_unlocked():
           /* 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_unlocked(), 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_unlocked(), 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
       attributes(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_unlocked(),    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
       This  page  is  part of release 4.15 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.
                                  2017-09-15                 UNLOCKED_STDIO(3)