Insert Function before and after main function

#include<stdio.h>

void myStartupFun (void) __attribute__ ((constructor));

void myCleanupFun (void) __attribute__ ((destructor));

/* implementation of myStartupFun */

void myStartupFun (void)

{

    printf ("startup code before main()\n");

}

/* implementation of myCleanupFun */

void myCleanupFun (void)

{

    printf ("cleanup code after main()\n");

}

int main (void)

{

    printf ("hello\n");

    return 0;

}