Process the specified function at exit.
| #include <stdlib.h> | Required only for function declarations |
int atexit( void ( __cdecl *func )( void ) );
int __far _fatexit( void ( __cdecl __far *func )( void ) );
| func | 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. No more than 32 functions can be registered with atexit or _onexit. The functions passed to atexit cannot take parameters.
For DOS32X, 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.
The _fatexit function is a far version of atexit; it can be used with any memory model.
Both atexit and _fatexit return 0 if successful, or a nonzero value if an error occurs (e.g., if there are already 32 exit functions defined).
atexit
Standards:ANSI
16-Bit:DOS, QWIN, WIN, WIN DLL
32-Bit:DOS32X
Use the ANSI-standard atexit function (rather than the similar _onexit function) whenever ANSI portability is desired._fatexit
Standards:None
16-Bit:DOS, QWIN, WIN, WIN DLL
32-Bit:None
/* 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.