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/* ATEXIT.C illustrates function:
 *      atexit          onexit
 */
 
#include <stdlib.h>
#include <stdio.h>
#define ANSI                /* Comment out to try onexit     */
 
/* Prototypes */
void fn1( void ), fn2( void ), fn3( void ), fn4( void );
 
void main()
{
 
    /* atexit is the ANSI standard. It returns 0 for success, nonzero
     * for fail.
     */
#if defined( ANSI )
    atexit( fn1 );
    atexit( fn2 );
    atexit( fn3 );
    atexit( fn4 );
 
    /* onexit is a Microsoft extension. It returns a pointer to a function
     * for success, NULL for fail.
     */
#else
    onexit( fn1 );
    onexit( fn2 );
    onexit( fn3 );
    onexit( fn4 );
#endif
 
    printf( "This is executed first.\n" );
}
 
void fn1()
{
    printf( "next.\n" );
}
 
void fn2()
{
    printf( "executed " );
}
 
void fn3()
{
    printf( "is " );
}
 
void fn4()
{
    printf( "This " );
}