_putc_nolock, _putwc_nolock

Writes a character to a stream without locking the thread.

int _putc_nolock(
   int c,
   FILE *stream 
wint_t _putwc_nolock(
   wchar_t c,
   FILE *stream 


Character to be written.


Pointer to the FILE structure.

See putc, putwc.

_putc_nolock and _putwc_nolock are identical to the versions without the _nolock suffix except that they are not protected from interference by other threads. They might be faster because they do not incur the overhead of locking out other threads. Use these functions only in thread-safe contexts such as single-threaded applications or where the calling scope already handles thread isolation.

_putwc_nolock is the wide-character version of _putc_nolock; the two functions behave identically if the stream is opened in ANSI mode. _putc_nolock doesn't currently support output into a UNICODE stream.

Generic-Text Routine Mappings

Tchar.h routine

_UNICODE and _MBCS not defined

_MBCS defined

_UNICODE defined






Required header




<stdio.h> or <wchar.h>

For more compatibility information, see Compatibility in the Introduction.


All versions of the C run-time libraries.

// crt_putc_nolock.c
/* This program uses putc to write buffer
 * to a stream. If an error occurs, the program
 * stops before writing the entire buffer.

#include <stdio.h>

int main( void )
   FILE *stream;
   char *p, buffer[] = "This is the line of output\n";
   int  ch;

   ch = 0;
   /* Make standard out the stream and write to it. */
   stream = stdout;
   for( p = buffer; (ch != EOF) && (*p != '\0'); p++ )
      ch = _putc_nolock( *p, stream );

This is the line of output

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