C语言wait()函数:结束(中断)进程函数(常用)
相关函数:waitpid, fork
头文件:#include <sys/types.h> #include <sys/wait.h>
定义函数:pid_t wait (int * status);
函数说明:wait()会暂时停止目前进程的执行, 直到有信号来到或子进程结束. 如果在调用wait()时子进程已经结束, 则wait()会立即返回子进程结束状态值. 子进程的结束状态值会由参数status 返回, 而子进程的进程识别码也会一快返回. 如果不在意结束状态值, 则参数 status 可以设成NULL. 子进程的结束状态值请参考waitpid().
返回值:如果执行成功则返回子进程识别码(PID), 如果有错误发生则返回-1. 失败原因存于errno 中.
范例
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
main()
{
pid_t pid;
int status, i;
if(fork() == 0)
{
printf("This is the child process. pid =%d\n", getpid());
exit(5);
}
else
{
sleep(1);
printf("This is the parent process, wait for child...\n";
pid = wait(&status);
i = WEXITSTATUS(status);
printf("child's pid =%d . exit status=^d\n", pid, i);
}
}
执行:
This is the child process. pid=1501
This is the parent process, wait for child...
child's pid =1501, exit status =5
头文件:#include <sys/types.h> #include <sys/wait.h>
定义函数:pid_t wait (int * status);
函数说明:wait()会暂时停止目前进程的执行, 直到有信号来到或子进程结束. 如果在调用wait()时子进程已经结束, 则wait()会立即返回子进程结束状态值. 子进程的结束状态值会由参数status 返回, 而子进程的进程识别码也会一快返回. 如果不在意结束状态值, 则参数 status 可以设成NULL. 子进程的结束状态值请参考waitpid().
返回值:如果执行成功则返回子进程识别码(PID), 如果有错误发生则返回-1. 失败原因存于errno 中.
范例
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
main()
{
pid_t pid;
int status, i;
if(fork() == 0)
{
printf("This is the child process. pid =%d\n", getpid());
exit(5);
}
else
{
sleep(1);
printf("This is the parent process, wait for child...\n";
pid = wait(&status);
i = WEXITSTATUS(status);
printf("child's pid =%d . exit status=^d\n", pid, i);
}
}
执行:
This is the child process. pid=1501
This is the parent process, wait for child...
child's pid =1501, exit status =5