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From: steve@taumet.com (Stephen Clamage)
Newsgroups: comp.lang.c++
Subject: Re: macros (was: const vs. static in class declaration)
Keywords: macros, inline
Message-ID: <660@taumet.com>
Date: 6 Apr 91 17:59:45 GMT
References: <3864@island.COM> <1991Apr3.202015.7402@csi.uottawa.ca> <657@taumet.com> <1991Apr5.211511.19618@csi.uottawa.ca>
Distribution: na
Organization: Taumetric Corporation, San Diego
Lines: 33

>In article <657@taumet.com> steve@taumet.com (Stephen Clamage) writes:
>>hitz@sim5.csi.uottawa.ca (Martin Hitz) writes:
>>
>>>However, I *do* use a define in such a case to avoid declaration of
>>> N inline functions for N arrays:
>>
>>>#define DIM(array) (sizeof(array)/sizeof(*array))
>>
>>ARRRRGGGGHHH!  Use inline member or non-member functions to do this.
>>They will be evaluated at compile time by any decent compiler, and
>>it avoids the nasty problems of mismatched types and unscoped names
>>endemic to macros.  

Sigh.  I guess I didn't explain myself well enough.  I didn't mean that
the macro DIM could be replaced by an inline function.  It can't.  I
meant that we should be looking for C++ solutions to our programming
problems rather than rehashing old C tricks.  Macros have lots of
problems (I pointed out two with the DIM macro), and IMHO are almost
never needed.

The DIM macro can only work when the array is declared with a compile-time
constant.  So why not give that constant a name?
	const int x_size = 10;
	T x[x_size];		// T is some type
	const int y_size = x_size + 2;
	U y[y_size];		// U is some type
For classes containing dynamic arrays, it makes sense to have an inline
member function returning data about its size.

Anyhow, that's my ARRRRGGGGHHHument (thanks, Martin, for that locution).
-- 

Steve Clamage, TauMetric Corp, steve@taumet.com