atexit

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

void bye()
{
    printf("byte\n");
}

void goodbyte()
{
    printf("good byte\n");
}

int main(int argc, char *argv[])
{
    atexit(bye);	//bye will be called after exit
    atexit(goodbyte); //goodbyte will be called after exit
    printf("hello\n");
    return 0;
}