GETC_UNLOCKED(3) Library Functions Manual GETC_UNLOCKED(3)

getc_unlocked getchar_unlocked putc_unlocked putchar_unlocked — stdio with explicit client locking

#include <stdio.h>

int getc_unlocked(FILE *stream);
int getchar_unlocked(void);
int putc_unlocked(int c, FILE *stream);
int putchar_unlocked(int c);

Versions of the functions getc(3) , getchar(3) , putc(3) , and putchar(3) respectively named getc_unlocked() , getchar_unlocked() , putc_unlocked(3) , and putchar_unlocked(3) are provided which are functionally identical to the original versions with the exception that they are not required to be implemented in a thread-safe manner. They may only safely be used within a scope protected by flockfile(3) (or ftrylockfile(3) ) and funlockfile(3) . These functions may safely be used in a multi-threaded program if and only if they are called while the invoking thread owns the ( FILE * ) object, as is the case after a successful call of the flockfile(3) or ftrylockfile(3) functions.

See getc(3) , getchar(3) , putc(3) , and putchar(3) .

No errors are defined.

None.

Because they may be implemented as macros, getc_unlocked() and putc_unlocked() may treat incorrectly a stream argument with side effects. In particular, getc_unlocked (* f ++) and putc_unlocked (* f ++) will not necessarily work as expected. Therefore, use of these functions should be preceded by the appropriate "#undef getc_unlocked" or "#undef putc_unlocked" statement in such situations.

None.

getc(3) , getchar(3) , putc(3) , putchar(3) , <stdio.h> .

Derived from the POSIX Threads Extension (1003.1c-1995)

February 1997 posix.fail