#include "signal.h"
#include "unistd.h"

static void my_op(int);
main()
{
   sigset_t new_mask,old_mask,pending_mask;
   struct sigaction act;
   sigemptyset(&act.sa_mask);
   act.sa_flags=SA_SIGINFO;
   act.sa_sigaction=(void*)my_op;
   if(sigaction(SIGRTMIN+10,&act,NULL))
       printf("install signal SIGRTMIN+10 error\n");
   sigemptyset(&new_mask);
   sigaddset(&new_mask,SIGRTMIN+10);
   if(sigprocmask(SIG_BLOCK, &new_mask,&old_mask))
       printf("block signal SIGRTMIN+10 error\n");
   sleep(10);
   printf("now begin to get pending mask and unblock SIGRTMIN+10\n");
   if(sigpending(&pending_mask)<0)
       printf("get pending mask error\n");
   if(sigismember(&pending_mask,SIGRTMIN+10))
       printf("signal SIGRTMIN+10 is pending\n");
   if(sigprocmask(SIG_SETMASK,&old_mask,NULL)<0)
       printf("unblock signal error\n");
   printf("signal unblocked\n");
   sleep(10);
}

static void my_op(int signum)
{
   printf("receive signal %d \n",signum);
}