C99: Suggestions for style(9)

[M. Warner Losh]

In message: <49FADEF3.5010106 at gmx.de>
            Christoph Mallon <christoph.mallon at gmx.de> writes:
: Marius Strobl schrieb:
: > On Sun, Apr 26, 2009 at 09:02:36AM +0200, Christoph Mallon wrote:
: >> return with parentheses:
: >> Removed, because it does not improve maintainability in any way. There 
: >> is no source for confusion here, so the rule even contradicts the rule, 
: >> which states not to use redundant parentheses. Maybe, decades ago it was 
: >> just a workaround for a broken compiler, which does not exist anymore.
: > 
: > FYI, the idea behind this rule is said to be to able to use
: > a macro return(), f.e. for debugging you then can do:
: > #define	return(x) do {							\
: > 	printf("returning from %s with %d\n", __func__, (x));		\
: > 	return (x);							\
: > } while (0)
: > 
: > Given the this is a nifty feature and parentheses around the
: > return value don't hurt maintainability in any way IMO this
: > rule should stay.
: 
: This is mentioned nowhere in style(9) (in general it is lacking reasons 
: why something is some way or the other).

It has been an example used for the past 15 years at least as to why
to do this...  I don't know how many people have actually used the
ability to do this in code.

: Also I consider this as gross abuse: Macro names shall be in all 
: uppercase, so it is clear that there is a macro at work. Therefore 
: "return" is not a candidate. So this would violate yet another rule in 
: style(9) (the original return already violates the no-redundant 
: parentheses rule).
: Also I would not mention __func__: there were objections against using 
: it in the past (though I, logically, prefer its use).

It is a debugging aid, but one of dubious value for a far more
fundamental reason:

	    return;

will break any macro.

Warner