标题: 关于子进程的返回值问题请教 [打印本页] 作者: robinchris 时间: 2006-06-06 11:45 标题: 关于子进程的返回值问题请教 在advanced linux programming中，有下面一段，然后写了一点代码想测试一下，发现不对，是不是我的理解有问题？
Note that even though the parameter type of the exit function is int and the main function returns an int,Linux does not preserve the full 32 bits of the return code.In fact,you should use exit codes only between zero and 127.Exit codes above 128 have a special meaning—when a process is terminated by a signal,its exit code is 128 plus the signal number.
测试代码如下：
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
int main()
{
int chld_status;
pid_t pid;
pid=fork();
if(pid>0)
{
printf("Parent process,and child process:%d\n",pid);
wait(&chld_status);
printf("child process return value:%d\n",WEXITSTATUS(chld_status));
return 0;
}else{
printf("Child process pid:%d\n",getpid());
sleep(20);
return 0;
}
}
如果不向子进程发signal，结果如下：
Child process pid:14879
Parent process,and child process:14879
child process return value:0
如果向子进程发signal（kill -SIGTERM 14887），结果如下：
Child process pid:14887
Parent process,and child process:14887
child process return value:0