Subj : Re: sigwait() is not catching SIGUSR1 signal
To   : comp.programming.threads,comp.unix.programmer
From : neelakantan
Date : Sat Mar 12 2005 07:24 am

> Your program looks OK... Although you should be checking the return 
> status of sigwait(). Right now, if it were to fail, you'd go into an 
> infinite hot loop.
> 
> I wonder if you could be running LinuxThreads? That might explain why it 
> works when you use the kill(1) but not when the program uses kill(2). 
> LinuxThreads was able to manage only a loose approximation of the POSIX 
> process model; and one of the weakest areas was signal handling. In 
> particular, there was no such thing as a "process pending signal mask"; 
> a blocked signal would "stick" to the thread it hit first. When you 
> kill(1) the "process", externally, it may hit the main thread (which is 
> blocked in sigwait() and takes the signal as you expect), while the 
> kill(2) from within a different thread delivers the signal to itself, 
> finds it blocked, and pends against that thread... never reaching the 
> main thread's sigwait(). NGPT, however, shouldn't have this problem, and 
> I thought that was the default on Red Hat 9...

Hi,
   If linuxThreads behaves so, Is it not violating the semantics that
is mentioned in the man page of sigwait()?. I despiratly need a way
out from this problem?
Any suggestions will be highly appreciated.

Thanks and regards,
Neelakantan.

.