UNLOCKED_STDIO(3)

NAME
getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked - nonlocking 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 without 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 ALSO
flockfile(3), stdio(3), feature_test_macros(7)

COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.