program without main

no_main.c

// gcc -o no_main no_main.c -nostartfiles

#include <stdio.h>

extern void _exit (register int code);

_start()
{
  int retval;
  retval = my_main ();
  _exit(retval);
}

int my_main(void)
{
  printf("Hello\n");
  return 0;
}