unlocked_stdio(3)	    Library Functions Manual	       unlocked_stdio(3)

NAME
     getc_unlocked, getchar_unlocked, putc_unlocked, putchar_unlocked - nonlock-
     ing 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 oth-
     ers) and hence are thread-unsafe.	See flockfile(3).

ATTRIBUTES
     For an explanation of the terms used in this  section,  see  attributes(7).
     allbox; lb lb lbx l l l.  Interface Attribute Value T{ 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() T}	 Thread
     safety  T{ MT-Safe race:stream T} T{ getchar_unlocked(),
     getwchar_unlocked() T}   Thread safety  T{ MT-Unsafe race:stdin T} T{
     putchar_unlocked(), putwchar_unlocked() T}	  Thread safety	 T{ MT-Unsafe
     race:stdout T} T{ feof_unlocked(), ferror_unlocked(), fileno_unlocked()
     T}	  Thread safety	  MT-Safe

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 6.18		   2026-02-08		       unlocked_stdio(3)