[Linux]关于sigprocmask函数的讨论

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <signal.h>
 #include <assert.h>

 void printSignal()
 {
     sigset_t set;
     int ret = ;
     sigemptyset(&set);
     ret = sigpending(&set);
     int i = ;
     for (i = ; i < ; i++)
     {
         if ( == (ret = sigismember(&set, i)))
         {
             printf("");
         }
         else if ( == ret)
         {
             printf("");
         }
     }
     puts("");
 }

 void my_sigaction (int num, siginfo_t *st, void *dat)
 {
     int ret = ;
     if (SIGINT == num)
     {
         sigset_t set;
         sigemptyset(&set);
         ret = sigaddset(&set, SIGQUIT);
         assert(- != ret);
         ret = sigprocmask(SIG_UNBLOCK, &set, NULL);
         assert(- != ret);
         printf("my_sigaction\n");
         printSignal();
         printf("func myhandler num = %d\n", num);
     }
     else
     {
         printf("signal is  no SIGQUIT\n");
     }
 }

 int main(void)
 {
     int ret = ;

     /* 阻塞信号  */
     sigset_t set;
     sigemptyset(&set);
     ret = sigaddset(&set, SIGQUIT);
     assert(- != ret);
     ret = sigprocmask(SIG_BLOCK, &set, NULL);
     assert(- != ret);
     printf("阻塞信号\n");
     //printSignal();
     sigemptyset(&set);
     /*
 sigpending 是从未决状态字中读取的， 但是未决信号并不能立即得到block的同步
 也就是说在block置1时pending并不能够立即的更新为1
 */
     //sigpending(&set);

     /* 注册信号 */
     struct sigaction act;
     act.sa_sigaction = my_sigaction;
     ret = sigemptyset(&(act.sa_mask));
     assert(- != ret);
     ret = sigaction(SIGINT, &act, NULL);
     assert(- != ret);
     printf("注册信号\n");
     printSignal();

     while ()
     {
         printSignal();
         sleep();
     }
     return ;
 }