p8-20.c

SUN Solaris8平台下进程间通信

#include <stdio.h>
#include <sys/types.h>
#include <sys/siginfo.h>
#include <sys/signal.h>
volatile pid_t pkid;
/* SIGHCLD信号句柄.注意:技术上不支持信号句柄内调用printf,此处仅用于举例目的.*/
void sigchld_handler(int sig, siginfo_t *sip, void *extra)
{
     pid_t kid;
     kid = sip->si_pid;
     if (sip->si_code <= 0){  /* 子进程收到由其它进程发送的信号 */
         printf("KILLED BY %d: Got signal %d, si_code %d for kid %d\n",
                 sip->si_pid, sip->si_signo, sip->si_code,getpid());
         exit(0);      /* 收到信号后正常终止,这将导致父进程进入该句柄 */
     }
     /* 父进程执行的代码 */      
     else if (sip->si_code == CLD_EXITED) 
         printf("EXIT: Got signal %d, si_code %d for kid %d\n",
                 sip->si_signo, sip->si_code, kid);
     else if (sip->si_code == CLD_DUMPED) 
         printf("ABORT: Got signal %d, si_code %d for kid %d\n",
                sip->si_signo, sip->si_code, kid);
     else if (sip->si_code == CLD_KILLED) 
         printf("KILLED: Got signal %d, si_code %d for kid %d\n",
                sip->si_signo, sip->si_code, kid);    
     kid = wait(0); 
     printf("Parent got PID %d exiting\n\n", kid);
     pkid = 0;         /* 设置信号处理完毕标志 */
}
int main(void)
{
    struct sigaction sa;
     /* 设置SIGHCLD句柄 */
     sa.sa_sigaction = sigchld_handler;
     sigemptyset(&sa.sa_mask);
     sa.sa_flags = SA_SIGINFO;
     if (sigaction(SIGCHLD, &sa, 0)) {
         perror("sigaction");
         exit(1);
     }
     printf("I am father,My pid=%d\n",getpid());
     /* 创建一个子进程,该子进程先被kill然后从句柄内正常终止.*/ 
     if (pkid = fork()){
         printf("Parent forked %d\n", pkid);
         printf("Parent will kill %d\n", pkid);
         kill(pkid,SIGCHLD);
     } else {        /* 第一个子进程 */  
         printf("Kid %d will be killed.\n", getpid());             
         while(1);   /* 等待信号后终止 */
     }
     /*  父进程:忙等待直到子进程退出. */
     while (pkid);
     /* 创建一个子进程,该子进程将由于SIGABRT而死去 */ 
     if (pkid = fork())
         printf("Parent forked %d\n", pkid);
     else {         /* 第二个子进程 */   
         sleep(1);
         printf("Kid %d will now die with core file.\n",getpid());
         abort();
     }
     /* 父进程:忙等待直到子进程退出. */
     while(pkid);
     printf("Parent: done\n" );
}