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


volatile int flag = 0;

void action(int sig) {
    static int val = 0;
    flag = 1;
    if (sig == SIGUSR1) {
        val += 5;
    } else if (sig == SIGUSR2) {
        val -= 4;
    }
    printf("%d %d\n", sig, val);
    fflush(stdout);
    if (val < 0) {
        exit(0);
    }
}


int main(int argc, char *argv[]) {
    printf("%d\n", getpid());
    fflush(stdout);
    struct sigaction act = {};
    act.sa_handler = action;
    sigset_t set, oldset;
    sigemptyset(&set);
    sigaddset(&set, SIGUSR1);
    sigaddset(&set, SIGUSR2);
    act.sa_mask = set;
    sigaction(SIGUSR1, &act, 0);
    sigaction(SIGUSR2, &act, 0);
    while (1) {
        while (!flag) {
            sigsuspend(&oldset);
        }
        flag = 0;
    }
    return 0;
}