#define    EXIT_SUCCESS    0 
#define    EXIT_FAILURE    1 

#include <stdlib.h>
void exit(int status);
void _Exit(int status);
#include <unistd.h>
void _exit(int status);

#include<stdlib.h>
int atexit(void (*function)(void))

#include<stdlib.h>
#include<unistd.h>
static void my_exit1()
{
printf("first exit handlern\n");
}

static void my_exit2()
{
 printf("second exit handlern\n");
}

int main()
{
 if (atexit(my_exit2) != 0)
printf("can't register my_exit2n\n");
 if (atexit(my_exit1) != 0)
printf("can't register my_exit1n\n");
 if (atexit(my_exit1) != 0)
printf("can't register my_exit1n\n");

 printf("main is donen\n");
 return 0;
}

addia@addia-Lenovo-B470:~$ ./test
main is donen
first exit handlern
first exit handlern
second exit handlern