Comments on: Variable length C macros

By: Maciej Mrozowski

Maciej Mrozowski — Fri, 15 Jan 2010 18:42:43 +0000

Err, I may be missing something, but following code always worked for me in GCC:

#define FORMAT(level,format,args …) “%-6s [%s] “format, #level, logger->name.c_str(), ##args

so:

#define macro(args …) call_function(##args)

(I see Torbjörn provided link for it)

By: Torbjörn Andersson

Torbjörn Andersson — Tue, 02 Jun 2009 09:55:23 +0000

It should perhaps be pointed out that this form of variadic macros is a GCC extension. Nothing wrong with that, but I think it’s good to be aware of it. It’s been there for as long as I can remember, and I might even have used it once or twice myself:

http://gcc.gnu.org/onlinedocs/gcc-4.4.0/gcc/Variadic-Macros.html

The CPP manual has some more information, but I haven’t had the time to digest it. There does seem to be a couple of ways of dealing with the trailing comma, but unfortunately they too are GCC extensions:

http://gcc.gnu.org/onlinedocs/cpp/Variadic-Macros.html

By: Michael Simms (CEO and head of Development)

Michael Simms (CEO and head of Development) — Sat, 30 May 2009 17:14:01 +0000

Thanks {:-)
(If Id binned it, I wouldnt have been able to say thanks, so, I kept it)

By: Max

Max — Sat, 30 May 2009 11:14:15 +0000

Quite good that you find out about these solutions and even better that you release them, might come in handy one day when someone is doing something similar.
The main problem in coding is actually to find out about all the capabilities a language has to offer.
Actually that seems to be the main problem with many things.
Most of the time you just don’t know that certain things are allowed.

By: RK

RK — Sat, 30 May 2009 10:00:50 +0000

Typo: “This means that in gcc, is you wanted to create a define…”
“is” should be “if” in this sentence.

Feel free to Moderate this comment into oblivion once you’ve fixed the typo. :)