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From: wescott@sauron.UUCP (Mike Wescott)
Newsgroups: comp.lang.c++
Subject: Re: Problem making cfront 1.1 on 4.3BSD
Message-ID: <765@sauron.UUCP>
Date: Mon, 24-Nov-86 12:13:03 EST
Article-I.D.: sauron.765
Posted: Mon Nov 24 12:13:03 1986
Date-Received: Tue, 25-Nov-86 03:20:36 EST
References: <3960003@nucsrl.UUCP>
Reply-To: wescott@sauron.UUCP (Mike Wescott)
Organization: NCR Corp., Advanced System Development, Columbia, SC
Lines: 40

In article <3960003@nucsrl.UUCP> gore@nucsrl.UUCP (Jacob Gore) writes:
> Now I have a problem with making cfront, and also a question about some
> code in src/main.c.
> 
> The question I have is about a related portion of src/main.c:
> ===================================
> 	typedef void (*ST)(...);	// trick to circumvent problems with old
> 	ST sick = ST(&signal);		// (or C) versions <signal.h>
> 	sick(SIGILL,core_dump);
> 	...
> ===================================
> Now, if I understand this correctly, 'sick' is a pointer to the 'signal'
> function.  In that case, shouldn't the call be "(*sick)(SIGILL,core_dump);"?

Not necessarily.  Both expressions are equivalent in C++ as well as in C.
For C++, see "The C++ Programming Language" by B. Stroustrup, from the 
Reference Manual section 7.1:

	"    A function call is a primary expression followed by parentheses
	containing a possibly empty, comma-separated list of expressions which
	constitute the actual arguments to the function.  The primary
	expression must be of type ``function returning ...'' or ``pointer to
	function returning'', and the result of the function call is of type 
	``...''.


I can't find a similar blessing in K&R, but my reading of 3.3.2.2 of the July 9
draft of the ANSI-C standard leads me to believe that it is legit in C as
well.  Besides, the compilers take it.  There is, however a bug in the way the
statement is converted to C.  The original code (version 1.1) would, on most
machines work and produce reasonable C code.  A recent fix to print.c posted
by Dr. Stroustrup fixed one problem but made the situation worse for compiling
this section of main.c.  I am posting another article with this fix and
another.

-- 
	-Mike Wescott
	 ncrcae!wescott