#include <sys/types.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>

pid_t mypid;

void usr1a(int sig);
void usr1b(int sig);

main () {

    mypid = getpid();

    /* SVR4 Signal improvements */
    /* generated, delivered, pending, blocked */
    /* the value of the function can be SIG_DFL - default or
					SIG_IGN - ignore this signal */


    sigset (SIGINT , SIG_IGN) ;
    sigset (SIGUSR1, usr1a);

    printf("Running as %d, hit me wtith an INT or USR1\n",mypid);
    while(1) ;

}

void usr1a (int sig) {

    sighold(sig);

    printf ("in usr1a, let's put a few sigusr1s in the queue\n");
    kill (mypid,SIGUSR1);
    kill (mypid,SIGUSR1);
    kill (mypid,SIGUSR1);
    printf("Put three SIGUSR1 out.  Resetting the handler to usr1b\n");

    sigset (SIGUSR1, usr1b);
    
    sigrelse(sig);
    printf("all done with usr1a\n");
}

void usr1b (int sig) {
    static int count = 0;

    printf ("in usr1b, count = %d \n",count++);
}