putc_unlocked()

Updated: April 19, 2023

Write a character to an output stream

Synopsis:

#include <stdio.h>

int putc_unlocked( int c, 
                   FILE *stream );

Arguments:

c
The character that you want to write.
stream
The stream you want to write the character on.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The putc_unlocked() function is a thread-unsafe version of putc(). You can use it safely only when the invoking thread has locked stream using flockfile() (or ftrylockfile()) and funlockfile().

Returns:

The character written, cast as (int)(unsigned char), or EOF if an error occurred (errno is set).

Classification:

POSIX 1003.1

Safety:  
Cancellation point Yes
Interrupt handler No
Signal handler No
Thread No