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.
Libraries
| 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.
Parameter
func
Function to be called
Remarks
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.
Example
/* 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 " );
}
Output
This is executed first.
This is executed next.