topic signal not delivered in Operating System - Linux

signal not delivered

Dubost_2 — Wed, 11 Oct 2006 09:44:56 GMT

I write a C program.
I set a signal handler for SIGTERM with sigaction. sigaction returns ok, everything seems fine.
A moment later, when the program is in a sleep(), I send a SIGTERM to the process. And the problem : the signal is not delivered, the process does not interrupt its sleep().
Has anyone encountered this problem. Why is my signal sometimes yes and sometimes not delivered ?

Re: signal not delivered

Peter Godron — Wed, 11 Oct 2006 09:59:33 GMT

Hi,
by design.

From man 3C sleep
"If a SIGALRM is generated for a multi-threaded process, it may not be delivered to a thread currently in sleep(). See sigwait(2) man page for details. In a multi-threaded process delivery of a SIGALRM to a
thread in sleep() simply causes sleep() to return without invoking the SIGALRM handler."

Re: signal not delivered

Dubost_2 — Wed, 11 Oct 2006 10:05:47 GMT

Hi,
Thank you for your answer.
This man page is not applicable.
My process is mono-threaded and I try to deliver the signal SIGTERM, not SIGALRM.