Path: utzoo!utgpu!cunews!mitel!melair!dataco!amodeo
From: amodeo@dataco.UUCP (Roy Amodeo)
Newsgroups: comp.lang.c
Subject: Re: Func Protos with K&R Func Defs
Message-ID: <503@dcsun21.dataco.UUCP>
Date: 13 Mar 91 18:00:09 GMT
References: <1991Mar1.030739.9683@nlm.nih.gov> <g8w5X2w163w@pondsquid.mv.com> <4865@goanna.cs.rmit.oz.au>
Reply-To: amodeo@dcsun03.UUCP (Roy Amodeo,DC )
Organization: Canadian Marconi Company (Datacomm), Ottawa, Ontario
Lines: 90

In article <4865@goanna.cs.rmit.oz.au> ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe) writes:
>
>All you have to do is take your ANSI C headers, stick a few more commas
>in, and add an identifier:
>
>#ifdef	__STDC__
>
>#define	PROTO(x)	x
>
>	...
>#define A2(t1,v1,t2,v2) \
>	(t1 v1, t2 v2)
>	...
>
>#else
>
>#define	PROTO(x)	()
>
>	...
>#define A2(t1,v1,t2,v2) \
>	(v1,v2) t1 v1; t2 v2;
>	...
>
>#endif
>
>The example then becomes
>    int tkline A2(
>	char*,       bufP,		/* Buffer pointer */
>	AREG1 char*, tbufP)		/* Token buffer pointer */
>	{ ... }
>
>All done by kindness.

A problem arises in the following case:

	int insert( char a[MAX_A], int (*func)( char a[] ) )
	{
	...
	}

So perhaps you should extend the macro to be

#ifdef	__STDC__

#define	A2( t1, v1, x1, t2, v2, x2 ) \
	(t1 v1 x1, t2 v2 x2 )

#else

#define	A2( t1, v1, x1, t2, v2, x2 ) \
	(v1, x1 ) t1 v1 x1; t2 v2 x2;

#endif

Then my example becomes:

	int insert( char,a,[MAX_A], int (*, func, ) PROTO(( char a[] )) )
	----------------------------------^^^^^^^

I don't think this will work because the commas inside the brackets are
supposed to separate the macro arguments, but I don't think they will because
they are in brackets.

So perhaps you have to do it with typedefs:

	typedef	int	(*intfunc_char) PROTO(( char a[] ));

	int insert A2( char,a,[MAX_A], intfunc_char, func, )
	{ ... }

which should work. Unfortunately the original example becomes:

	int tkline A2( char*, bufP,, intfunc_char, func, )

The double commas are obnoxious and errors involving them might be a pain to
find. The necessity to typedef function pointers is worse. The best solution
is to use all ANSI tools if possible. I wish we could.

Just thought you'd like to know what you're getting into.

rba iv
dataco!amodeo


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