Collapse the table of content
Expand the table of content
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here. ArchiveDisclaimer


Set the value of the errno global variable.

errno_t _set_errno( 
   int value 


[in] value

The new value of errno.

Returns zero if successful.

Possible values are defined in Errno.h. Also, see errno Constants.

// crt_set_errno.c
#include <stdio.h>
#include <errno.h>

int main()
   _set_errno( EILSEQ );
   perror( "Oops" );


Oops: Illegal byte sequence

Routine Required header Optional header Compatibility




Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003

For more compatibility information, see Compatibility in the Introduction.

© 2015 Microsoft