Path: utzoo!attcan!uunet!virtech!cpcahil
From: cpcahil@virtech.UUCP (Conor P. Cahill)
Newsgroups: comp.unix.questions
Subject: Re: SunOS: 1; portability: 0
Message-ID: <1195@virtech.UUCP>
Date: 23 Sep 89 02:18:18 GMT
References: <880@cirrusl.UUCP>
Organization: Virtual Technologies Inc
Lines: 28

In article <880@cirrusl.UUCP>, dhesi@sun505.UUCP (Rahul Dhesi) writes:
> For about ten years, signal() has been a function returning pointer to
> int.  It worked, and we were all happily writing portable code.

No, signal(2) now returns a pointer to a function returning void.

> After much thinking I have found no advantage to this change, and the
> big disadvantage that stable existing code now brreaks.

Since signal() returns the pointer to the old signal handler or signal
handling status, and a signal handler, being called asynchronously with
respect to the rest of the code in the program, does not "return" a value
the "type" of a signal handler should be void.

> Now I'm faced with this problem:  How do I use signal() in such a way
> that my code is portable, without manually editing it for each
> implementation?   I need a way of having my code automatically use void
> or int as appropriate.

How about cc arg "-DSIGNAL_TYPE=void" and using it as:

	SIGNAL_TYPE	(*signal())();

-- 
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| Conor P. Cahill     uunet!virtech!cpcahil      	703-430-9247	!
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