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Manual Reference Pages  - UNLOCKED_STDIO (3)

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*_unlocked - non-locking stdio functions

CONTENTS

Synopsis
Description

#include <stdio.h> 



int getc_unlocked(FILE *stream); 

int getchar_unlocked(void); 

int putc_unlocked(int c, FILE *stream); 

int putchar_unlocked(int c); 



#define _BSD_SOURCE/*or_SVID_SOURCEor_GNU_SOURCE*/ 

#include <stdio.h> 



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); 



#define _GNU_SOURCE 

#include <stdio.h> 



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

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



#define _GNU_SOURCE 

#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); 

Each of these functions has the same behaviour 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).

The four functions getc_unlocked(), getchar_unlocked(), putc_unlocked(), putchar_unlocked() are in POSIX.1. The nonstandard *_unlocked() variants occur on a few Unix systems, and are available in recent glibc. They should probably not be used.

flockfile(3)

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