I'm newbie in UNIX programming, I have a problem with signals. I'm writing multithread program, where threads can die at any moment. When thread dies it generates signal SIGUSR1 to main thread and then thread dies. Main thread gets a signal and waits for thread dead.
I wrote program like this:
I've got a problem: some signals were not sended/received and I've got deadlock (main thread waits for signal, but signal never comes).
Program prints:
After it program locks.
Why some signals were not received? Program should send/recive 3 SIGUSR1 and exit, but there are only 2 SIGUSR1. Why?
Last edited by DendyGamer; 12-02-2011 at 04:56 AM..
Why "signal safety" may change something? Signals are blocked, when signal action called.
Ok, I've found list of async-signal-safe functions. I've replaced pthread_join by sleep(3) and system() by sleep(2) - nothing changed - I'm getting deadlock ( sleep() is async-signal-safe function ) .
Last edited by DendyGamer; 12-02-2011 at 12:06 PM..
Why "signal safety" may change something? Signals are blocked, when signal action called.
It means, you're not allowed to call pthread_join(*s,NULL); inside a signal handler, and the results can't be predicted when you do so. It may work and betray you in strange ways later. It may do incorrect things in a less than obvious way. It may blow up immediately. It may work in this system but fail when ported to another system or your kernel is upgraded. In short, you're not supposed to do it.
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let me explain my problem clearly..
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