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From: wolfe@winston.UUCP (Peter Wolfe)
Newsgroups: net.unix-wizards
Subject: Re: 4.2BSD and Signals
Message-ID: <174@winston.UUCP>
Date: Fri, 24-Jan-86 12:33:07 EST
Article-I.D.: winston.174
Posted: Fri Jan 24 12:33:07 1986
Date-Received: Sat, 25-Jan-86 06:42:29 EST
References: <173@winston.UUCP>
Reply-To: wolfe@winston.UUCP (Peter Wolfe)
Organization: New Media Technologies, Burnaby, BC, CANADA
Lines: 30
Summary: 

Well, is my face slightly red or what!!!  I discovered what the problem
was.

The man page for sig block says:

     Signal i is blocked if the i-th bit in mask is a 1.
    
well, what they really want you to do is:

    to block signal X set the (X-1) bit in the mask

    E.g.

	sigblock(1 << (SIGVTALRM - 1));

    will block SIGVTALRM.

Of course once I had posted the article and described the problem to a
colleague the solution seemed obvious (I also looked at the kernel code and
noticed the (sig-1) used).

So there you have it.  Read the manual and read between the manual if
system == UNIX.

-- 

    Peter Wolfe
    New Media Technologies
    ..decvax!microsoft!ubc-vision!winston!wolfe
    ..ihnp4!alberta!ubc-vision!winston!wolfe