Manpages - unlocked_stdio.3

getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked - nonlocking 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);

  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 *restrict ptr, size_t size, size_t n,
   FILE *restrict stream);
  size_t fwrite_unlocked(const void *restrict ptr, size_t size",size_t"n,
   FILE *restrict stream);

  char *fgets_unlocked(char *restrict s, int n",FILE*restrict"stream);
  int fputs_unlocked(const char *restrict s, FILE *restrict 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 *restrict ws, int n,
   FILE *restrict stream);
  int fputws_unlocked(const wchar_t *restrict ws,
   FILE *restrict 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 <= 2.23: */ _POSIX_C_SOURCE
          || /* Glibc <= 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 <= 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

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).

For an explanation of the terms used in this section, see *attributes*(7).

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.

*flockfile*(3), *stdio*(3)

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