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#include "apue.h"

#include <pthread.h>

sigset_t mask;

struct sigaction ignore, saveintr, savequit, sigusr1_act, sigusr2_act;

int usr1_count;

int usr2_count;

pthread_t tid1;

pthread_t tid2;

void *  thr_fn1(void *arg); 

void *  thr_fn2(void *arg); 

static void sigusr1_handler(int sign); 

static void sigusr2_handler(int sign); 

void *  thr_fn1(void *arg)

{

int err, signo;

int i ; 

sigaction(SIGUSR1, &sigusr1_act, NULL);

pthread_detach(pthread_self());

for (;;) 

{

if (  pthread_kill(tid2, SIGUSR2) == 0)

{

}

err = sigwait(&mask, &signo);

if (err != 0)

err_exit(err, "sigwait failed");

switch (signo) 

{

case SIGUSR1:

printf("\nget SIGUSR1...,usr1_count=%d \n",usr1_count--);

break;

default:

printf("unexpected signal %d\n", signo);

exit(1);

}

}

}

void *  thr_fn2(void *arg)

{

int err, signo;

int i ; 

sigaction(SIGQUIT, &savequit, NULL);

sigaction(SIGUSR1, &sigusr1_act, NULL);

pthread_detach(pthread_self());

for (;;) 

{

if (  pthread_kill(tid1, SIGUSR1) == 0)

{

}

err = sigwait(&mask, &signo);

if (err != 0)

err_exit(err, "sigwait failed");

switch (signo) {

case SIGUSR2:

printf("\nget SIGUSR2...,usr1_count=%d \n",usr1_count++);

break;

default:

printf("unexpected signal %d\n", signo);

exit(1);

}

}

}

static void sigusr1_handler(int sign)

{

usr1_count ++;

}

static void sigusr2_handler(int sign)

{

usr1_count ++;

}

int main(void)

{

int err;

sigset_t oldmask;

sigemptyset(&mask);

sigaddset(&mask, SIGQUIT);

sigaddset(&mask, SIGUSR1);

sigaddset(&mask, SIGUSR2);

sigusr1_act.sa_handler = sigusr1_handler;

sigusr2_act.sa_handler = sigusr2_handler;

if ((err = pthread_sigmask(SIG_BLOCK, &mask, &oldmask)) != 0)

err_exit(err, "SIG_BLOCK error");

err = pthread_create(&tid1, NULL, thr_fn1, 0);

if (err != 0) err_exit(err, "can't create thread");

err = pthread_create(&tid2, NULL, thr_fn2, 0);

if (err != 0) err_exit(err, "can't create thread");

sleep (10); 

if (sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0)

{

err_sys("SIG_SETMASK error");

}

exit(0);

}