Constructors have to be called before the main function

Answer: yes

#include <stdio.h>
#include <conio.h>
 
/* Apply the constructor attribute to myStartupFun() so that it
    is executed before main() */
void myStartupFun (void) __attribute__ ((constructor));

 
/* Apply the destructor attribute to myCleanupFun() so that it
   is executed after main() */
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;
}