C语言库raise()函数

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>

void signal_catchfunc(int);

int main () {
   int ret;

   ret = signal(SIGINT, signal_catchfunc);

   if( ret == SIG_ERR) {
      printf(Error: unable to set signal handler.\n);
      exit(0);
   }
   printf(Going to raise a signal\n);
   ret = raise(SIGINT);

   if( ret !=0 ) {
      printf(Error: unable to raise SIGINT signal.\n);
      exit(0);
   }

   printf(Exiting...\n);
   return(0);
}

void signal_catchfunc(int signal) {
   printf(!! signal caught !!\n);
}