Re: [boost] Re: My try-out of the Felix Garbage Collector 1.1

From: John Max Skaller (skaller_at_[hidden])
Date: 2001-05-20 16:21:43

Daryle Walker wrote:
>
> You mean 2.95 for your GCC version, right?

        Yes.
 
> I don't think conformance in the way you're thinking of is possible with
> today's technology.  I think all #includes work today by text dumps, so a
> header that includes another header has to "leak" the symbols from the inner
> #include.  You should ignore that effect and directly #include the headers
> for any symbol you directly use.

        That isn't the case for macros: they can, and should, be 
#undef'd inside the header that uses them. 

        For types, the solution is to use implementor space
symbols: it doesn't matter if they leak. Same for functions.

        So it is certainly possible with todays technology,
and it is _required_ :-)

 
> Since <cassert> is supposed to help with user debugging, why would any
> standard header #include it?

        So inline functions can assert. But assert should be 
#undef'd at the end of the file if it was created by an inner include.

        #ifdef assert
        #define assert_defined
        #else
        #include <assert.h>
        #endif
        ...
        #ifndef assert_defined
        #undef assert
        #endif

This doesn't work if a non-standard assert is already defined,
but that would get crunched by an 'inner' assert anyhow.
A better technique is to use a vendor extension. :-)
 
-- 
John (Max) Skaller, mailto:skaller_at_[hidden]
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