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():
_POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE ||
_BSD_SOURCE || _SVID_SOURCE
clearerr_unlocked(), feof_unlocked(), ferror_unlocked(),
fileno_unlocked(), fflush_unlocked(), fgetc_unlocked(),
fputc_unlocked(), fread_unlocked(), fwrite_unlocked():
_BSD_SOURCE || _SVID_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).
CONFORMING TO
The four functions getc_unlocked(), getchar_unlocked(),
putc_unlocked(), putchar_unlocked() are in POSIX.1-2001.
The nonstandard *_unlocked() variants occur on a few UNIX systems, and
are available in recent glibc. They should probably not be used.
SEE ALSOflockfile(3), stdio(3)COLOPHON
This page is part of release 3.35 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://man7.org/linux/man-pages/.
2008-08-29 UNLOCKED_STDIO(3)
