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Subj : Re: Using SIGALRM with pthread
To   : comp.programming.threads
From : Ian
Date : Thu Jul 28 2005 04:44 pm

gc wrote:
> 
> At the same time, I need to use an ALARM signal (SIGALRM) in thread A
> to invoke a periodical even handler. I use the signal() function to
> install the handler for SIGALRM in thread A's constructor. In the
> SIGALRM handler, I also need to access some variables and data
> structures from thread A.
> 
Why not use another thread to do the wakeup?  No point complicating 
things with signals.

> What frustrates me is that, without turning on the ALARM signal,
> everything goes well. Whenever I turn on the ALARM signal, I get all
> kinds of werid errors related to pthread_mutexes. For instance,
> segmentation fault on pthread_mutex_unlock (unlock the mutex for the
> conditional variable), or sometimes thread B gets blocked on
> pthread_mutex_unlock (unlock does not return), or sometimes the whole
> program halts.
> 
Do you semaphore and condition objects cope with spurious wakeups or 
pthread_cond_wait returning after being interrupted by a signal?

Ian

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