Visual Studio 6.0

Processes the specified function at exit.

int atexit( void ( __cdecl *func )( void ) );

Routine Required Header Compatibility
atexit <stdlib.h> ANSI, Win 95, Win NT

For additional compatibility information, see Compatibility in the Introduction.


LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version

To generate an ANSI-compliant application, use the ANSI-standard atexit function (rather than the similar _onexit function).

Return Value

atexit returns 0 if successful, or a nonzero value if an error occurs.



Function to be called


The atexit function is passed the address of a function (func) to be called when the program terminates normally. Successive calls to atexit create a register of functions that are executed in LIFO (last-in-first-out) order. The functions passed to atexit cannot take parameters. atexit and _onexit use the heap to hold the register of functions. Thus, the number of functions that can be registered is limited only by heap memory.


/* ATEXIT.C: This program pushes four functions onto
 * the stack of functions to be executed when atexit
 * is called. When the program exits, these programs
 * are executed on a "last in, first out" basis.

#include <stdlib.h>
#include <stdio.h>

void fn1( void ), fn2( void ), fn3( void ), fn4( void );

void main( void )
   atexit( fn1 );
   atexit( fn2 );
   atexit( fn3 );
   atexit( fn4 );
   printf( "This is executed first.\n" );

void fn1()
   printf( "next.\n" );

void fn2()
   printf( "executed " );

void fn3()
   printf( "is " );

void fn4()
   printf( "This " );


This is executed first.
This is executed next.

Process and Environment Control Routines

See Also   abort, exit, _onexit