Re: Re: Re: boost::signals build and C++Builder 6 Pro in 1.29.0

From: Edward Diener (eddielee_at_[hidden])
Date: 2003-03-06 17:53:57

Paul Mensonides wrote:
> Edward Diener wrote:
>> Will a compiler correctly pick up the #pragma as a preprocessor line
>> or is the preprocessor stage finished once the macro is fully
>> expanded ? I believe the latter is true, although I could be wrong.
>
> It is not technically legal, but it might work anyway, as #pragmas
> usually aren't picked up by the preprocessor.
>
>> If I am right, then creating a Boost macro for these data layout
>> #pragmas for BCB and VC++, and any other compiler which lets one fix
>> data layout details such as packing from within each header file,
>> will not work. In that case the alternative of a easily remembered
>> header file name, which contains the appropriate #pragma, is a good
>> alternative for adding such #pragmas in the correct place of header
>> files which need such data layout reliability.
>
> Well, #pragmas that the compiler doesn't understand are supposed to
> be ignored. However, using a header for it is also a good option.
> You can even use a macro to introduce the header if you like:
>
> #include CREATE_PRAGMA()

Will the above really work ? I was always pretty sure that #includes have to
be processed before macros are expanded and not after.