Path: utzoo!attcan!uunet!lll-winken!lll-lcc!unisoft!mtxinu!rtech!llama!daveb
From: daveb@llama.rtech.UUCP (It takes a clear mind to make it)
Newsgroups: comp.unix.wizards
Subject: Re: #defines with variable # arguments
Message-ID: <2097@rtech.UUCP>
Date: 17 May 88 04:49:09 GMT
References: <2855@phoenix.Princeton.EDU> <52949@sun.uucp> <152@hropus.UUCP>
Sender: news@rtech.UUCP
Reply-To: daveb@rtech.UUCP (It takes a clear mind to make it)
Distribution: na
Organization: Relational Technology, Inc. Alameda, CA
Lines: 20

In article <152@hropus.UUCP> jgy@hropus.UUCP (John Young) writes:
>> >     Are there any versions of cpp which allow one to define macros which
>> > accept variable numbers of arguments?
>I think that some of the AT&T CPLU compilers(cpp's) allow this,
>you just overdeclare the arguments:
>
>#define   Dprintf(a,b,c,d,e,f,g,h,i) {if (Debug) printf(a,b,c,d,e,f,g,h,i);}
>
>and compile.  You will get a warning about each source line which uses
>the wrong number of arguments.

If you do 

#define Dprintf	if(Debug) printf

you don't get any warnings; you do get possible dangling else problems. 
This has rarely been a problem on the occasions I've usedthis technique.

-dB

{amdahl, cpsc6a, mtxinu, sun, hoptoad}!rtech!daveb daveb@rtech.uucp