unlocked_stdio(3)          Library Functions Manual          unlocked_stdio(3)

NAME
       getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked -
       nonlocking stdio functions

LIBRARY
       Standard C library (libc, -lc)

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 *_Nullable stream);

       int fgetc_unlocked(FILE *stream);
       int fputc_unlocked(int c, FILE *stream);

       size_t fread_unlocked(void ptr[restrict .size * .n],
                             size_t size, size_t n,
                             FILE *restrict stream);
       size_t fwrite_unlocked(const void ptr[restrict .size * .n],
                             size_t size, size_t n,
                             FILE *restrict stream);

       char *fgets_unlocked(char s[restrict .n], 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 ws[restrict .n], 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():
           /* 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 >= 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

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).

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

       +--------------------+---------------+---------------------------------+
       |Interface           | Attribute     | Value                           |
       +--------------------+---------------+---------------------------------+
       |getc_unlocked (),   | Thread safety | MT-Safe race:stream             |
       |putc_unlocked (),   |               |                                 |
       |clearerr_unlocked   |               |                                 |
       |(), fflush_unlocked |               |                                 |
       |(), fgetc_unlocked  |               |                                 |
       |(), fputc_unlocked  |               |                                 |
       |(), fread_unlocked  |               |                                 |
       |(), fwrite_unlocked |               |                                 |
       |(), fgets_unlocked  |               |                                 |
       |(), fputs_unlocked  |               |                                 |
       |(), getwc_unlocked  |               |                                 |
       |(), fgetwc_unlocked |               |                                 |
       |(), fputwc_unlocked |               |                                 |
       |(), putwc_unlocked  |               |                                 |
       |(), fgetws_unlocked |               |                                 |
       |(), fputws_unlocked |               |                                 |
       |()                  |               |                                 |
       +--------------------+---------------+---------------------------------+
       |getchar_unlocked    | Thread safety | MT-Unsafe race:stdin            |
       |(),                 |               |                                 |
       |getwchar_unlocked   |               |                                 |
       |()                  |               |                                 |
       +--------------------+---------------+---------------------------------+
       |putchar_unlocked    | Thread safety | MT-Unsafe race:stdout           |
       |(),                 |               |                                 |
       |putwchar_unlocked   |               |                                 |
       |()                  |               |                                 |
       +--------------------+---------------+---------------------------------+
       |feof_unlocked (),   | Thread safety | MT-Safe                         |
       |ferror_unlocked (), |               |                                 |
       |fileno_unlocked ()  |               |                                 |
       +--------------------+---------------+---------------------------------+
STANDARDS
       getc_unlocked()
       getchar_unlocked()
       putc_unlocked()
       putchar_unlocked()
              POSIX.1-2008.

       Others:
              None.

HISTORY
       getc_unlocked()
       getchar_unlocked()
       putc_unlocked()
       putchar_unlocked()
              POSIX.1-2001.

SEE ALSO
       flockfile(3), stdio(3)

Linux man-pages 6.7               2023-10-31                 unlocked_stdio(3)