Function before and after main()

Did you start to execute functions before and after the main() function ?

you have two solutions to do that :

first solution is editing in the linker script

the second one is adding these prototypes in your source code

void start( void ) __attribute__ ((constructor)) ;

void end( void ) __attribute__ ((destructor));

and define you functions by adding any instructions you want to execute like that for example

void start()

{

   printf("Start\n");

}

void end()

{

   printf("end\n");

}

int main()

{

printf("Hello");

}

Finally when you compile this program you get excited