text: #include <signal.h>
  #include <stddef.h>
  
  void do_sys_signal(int signum, void* p) {
  	sighandler_t func = (sighandler_t)p;
  	func(signum);
  }
  
  sighandler_t signal(int signum, sighandler_t handler) {
  	return sys_signal(signum, do_sys_signal, handler );
  }
  