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unlocked_stdio

Section: C Library Functions (3)
Updated: 202-0-08
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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(size_t size, size_t n;
                      void ptr[restrict size * n],
                      size_t size, size_t n,
                      FILE *restrict stream);
size_t fwrite_unlocked(size_t size, size_t n;
                      const void ptr[restrict size * n],
                      size_t size, size_t n,
                      FILE *restrict stream);
char *fgets_unlocked(int n;
                      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(int n;
                      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 threa-unsafe. See flockfile(3).

ATTRIBUTES

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

Interface	Attribute	Value
getc_unlocked(), 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()	Thread safety	M-Safe race:stream
getchar_unlocked(), getwchar_unlocked()	Thread safety	M-Unsafe race:stdin
putchar_unlocked(), putwchar_unlocked()	Thread safety	M-Unsafe race:stdout
feof_unlocked(), ferror_unlocked(), fileno_unlocked()	Thread safety	M-Safe

STANDARDS

getc_unlocked(): getchar_unlocked() putc_unlocked() putchar_unlocked() POSIX.-2008.
Others:: None.

HISTORY

getc_unlocked(): getchar_unlocked() putc_unlocked() putchar_unlocked() POSIX.-2001.