atexit
Processes the specified function at exit.
int atexit( void (__cdecl *func )( void ) );
Parameter
- func
- Function to be called.
Return Value
atexit returns 0 if successful, or a nonzero value if an error occurs.
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 last-in, first-out (LIFO) 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.
Requirements
| Routine | Required header | Compatibility |
|---|---|---|
| atexit | <stdlib.h> | ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.
To generate an ANSI-compliant application, use the ANSI-standard atexit function (rather than the similar _onexit function).
Example
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.
// crt_atexit.c
#include <stdlib.h>
#include <stdio.h>
void fn1( void ), fn2( void ), fn3( void ), fn4( void );
int 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.
See Also
Process and Environment Control Routines | abort, exit | _onexit | Run-Time Routines and .NET Framework Equivalents
