Re: [Boost-users] [bcp] [shared_ptr] Extracting subset ofboostforshared_ptr - 3.2MB?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2006-02-18 12:08:01

John Maddock wrote:

>> Unfortunately bcp isn't smart enough to not look into optional
>> dependencies that are guarded by #ifdef. In this particular case it
>> follows the dependency to detail/quick_allocator.hpp, which in turn
>> brings in the type_traits and mpl libraries. But quick_allocator.hpp
>> is only used if you #define BOOST_SP_USE_QUICK_ALLOCATOR.
>
> Peter, this comes up so often, I wonder is it worth while "hiding"
> that optional dependency behind a #define, as in:
>
> #define BOOST_SP_QA <some-header.hpp>
>
> #ifdef BOOST_SP_USE_QUICK_ALLOCATOR
> #include BOOST_SP_QA
> #endif
>
> Of course I have no data on how often that dependency is actually
> needed (or not).

How about something along the lines of:

bcp boost/shared_ptr.hpp --exclude=quick_allocator.hpp

Or:

#ifdef BOOST_SP_USE_QUICK_ALLOCATOR

//@bcp optional "quick_allocator is only used if explicitly requested"
#include <boost/detail/quick_allocator.hpp>

#endif

which would then inform the user that an optional dependency wasn't being 
followed (if this is the default):

    bcp: an optional dependency isn't included in the subset because

        `quick_allocator is only used if explicitly requested'

    bcp: use `bcp boost/shared_ptr.hpp boost/detail/quick_allocator.hpp' to 
include it

The advantage is that we don't have to decide whether to follow a particular 
dependency, the choice can be left to the person running bcp.