[Boost-users] Apple "Block" closures and boost::function

Subject: [Boost-users] Apple "Block" closures and boost::function
From: John M. Dlugosz (mpbecey7gu_at_[hidden])
Date: 2012-05-26 10:41:52

I'm looking at using Apple's proprietary closure blocks as a substitute for C++ lambda 
functions on a project that needs to be portable between Mac (LLVM 3.1, but not using the 
C++0x dialect compiler switch) and Windows (Visual Studio 10).  The project uses Boost.TR1 
to supply std::tr1::function and related stuff on the Mac build.

Now I found that the compiler handles the nonstandard block objects in Functor-like 
template situations in a manner perfectly analogous to C-style pointers to functions.  I 
can even assign one to a boost::function with no complaint!

The only issue seems to be that it never calls Block_copy/Block_release.  So it works OK 
for passing them to STL algorithms that uses them on the spot, but will probably do bad 
things if used in general.

Does anybody have something ready-made, to efficiently add the copy/destroy semantics to 
functors that hold such "blocks"?  That would be much more efficient than wrapping them in 
another layer.  Or, any pointers to the Boost innerds for doing that myself?

Thanks,
—John