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


 #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_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 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).


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.


flockfile(3), stdio(3), feature_test_macros(7)