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From: stuart@siesoft.co.uk (Stuart Hood)
Newsgroups: comp.lang.c
Subject: Macro arguments with commas
Summary: How do you pass an argument to a macro with a comma in
Keywords: Macro, comma
Message-ID: <1991Apr26.142042.11123@siesoft.co.uk>
Date: 26 Apr 91 14:20:42 GMT
Sender: usenet@siesoft.co.uk (NNTP Poster)
Distribution: comp
Organization: Siemens-Nixdorf Systems Development Group, UK
Lines: 39

I have a macro:

    #define M(E) { static int v[] = E; \
		   int i; \
		   for (i=0; i<sizeof(v)/sizeof(int); i++) \
		       process(v[i]); }

so that I can go:

    M({ 23 });

I would really love to go:

    M({ 23, 27 });

but this produces "incorrect bracketing" errors from the compiler
because '{' doesn't escape the parameter in the same way that '('
does.

The only solution that I can think of is:

    #define M(E) { int i=0; \
		   for (i=0; i<sizeof(E)/sizeof(int); i++) \
		       process(v[i]); }
    ...
    static int val = { 23, 27 };
    M(val);

Can anyone think of a neater solution?  Please email;  I'll post
the best solution (with due credits, of course).

Thanks in advance,

Stuart.
-
--
S I E M E N S  Stuart Hood === Siemens Nixdorf House, Bracknell, Berks, UK
-------------  Phone: + 44-344-850994          Email: stuart@siesoft.co.uk
N I X D O R F  The trouble with everyone, is that they generalise too much