C语言 我该如何处理 SIGCHLD？
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How can I handle SIGCHLD?
提问by kanoz
I need to handle SIGCHLDproperly. How can I use it with my existing code? at the moment I cant wait for the child process unless I use 0instead of WNOHANG|WUNTRACED.
我需要SIGCHLD妥善处理。如何将它与我现有的代码一起使用？目前我不能等待子进程，除非我使用0而不是WNOHANG|WUNTRACED.
status = 0;
pid_t child, endID;
if(amp == 1)
signal( SIGCHLD, SIG_IGN );
child = fork();
if (child < 0) {
perror("fork() error\n");
exit(EXIT_FAILURE);
} else if (child == 0) {
// do sth here
perror("error\n");
} else {
//sleep(1)
If I remove sleepthen parent is executed 1st.. why?
如果我删除sleep然后父级被执行 1st.. 为什么？
回答by cnicutar
Here is a start (but read below):
这是一个开始（但请阅读下文）：
static void
child_handler(int sig)
{
pid_t pid;
int status;
/* EEEEXTEERMINAAATE! */
while((pid = waitpid(-1, &status, WNOHANG)) > 0)
;
}
/* Establish handler. */
struct sigaction sa;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = child_handler;
sigaction(SIGCHLD, &sa, NULL);
Of course, this is all pointless. If the parent simply ignores SIGCHLD, the children are silently reaped and won't turn into zombies.
当然，这都是没有意义的。如果父母不理会SIGCHLD，孩子会默默地收获，不会变成僵尸。
Quoting TLPI:
引用TLPI：
Explicitly setting the disposition of SIGCHLD to SIG_IGN causes any child process that subsequently terminates to be immediately removed from the system instead of being converted into a zombie.
将 SIGCHLD 的处置显式设置为 SIG_IGN 会导致随后终止的任何子进程立即从系统中删除，而不是转换为僵尸进程。
So something like this should do the trick for you:
所以像这样的事情应该对你有用：
signal(SIGCHLD, SIG_IGN); /* Silently (and portably) reap children. */
