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");
}