> On Fri, Dec 11, 2009 at 12:48 PM, Jon <jon.forums@gmail.com> wrote:

> > From http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/22727 in the "Mixing runtime libraries" section the claim that you can mix msft c runtimes if
> >
> > * If you call ALLOC or ALLOC_N, use xfree and not free
> > * Don't call sprintf or printf in an extension, instead use rb_f_sprintf/rb_vsprintf/rb_io_printf
> >
> > ...does it make sense to change these free's to xfree's (not libffi's dlmalloc?) in ruby-ffi?
> >
> >
> > C:\Users\Jon\Documents\RubyDev\ffi-trunk>grep -Rn " free(" ext
> >
> > ext/ffi_c/Buffer.c:154:        free(ptr->storage);
> > ext/ffi_c/ClosurePool.c:131:        free(memory->data);
> > ext/ffi_c/ClosurePool.c:132:        free(memory);
> > ext/ffi_c/ClosurePool.c:135:    free(pool);
> > ext/ffi_c/ClosurePool.c:218:    free(block);
> > ext/ffi_c/ClosurePool.c:219:    free(list);
> > ext/ffi_c/libffi/src/dlmalloc.c:678:  free(void* p)
> > ext/ffi_c/libffi/src/dlmalloc.c:857:    free(pool);     // Can now free the array (or not, if it is needed later)
> > ext/ffi_c/MemoryPointer.c:137:            free(ptr->storage);
> > ext/ffi_c/Type.c:162:    free(type->name);
> >

> 
> libffi and the C extension are being built and linked against the same
> CRT version used by Ruby. That poses no risk for cross-CRT memory
> allocation and freeing.

Currently yes.

However, given the limited number of changes needed what do you see as the the downsides of removing this build restriction, assuming the specs pass?  Mod and maintenance of a version of dlmalloc distinct from libffi's?  I'm assuming (incorrectly?) that libffi's src currently isn't modified from the ftp://sources.redhat.com/pub/libffi/ dowloads.

> If was the case libffi was built with newer version of Visual Studio,
> which links to different CRT than Ruby itself, then I would worry to
> make the proper transition of all the free calls for xfree.

Not just paid versions of Visual Studio but also the Express editions and the command line compiler versions that msft is now including as part of the free Windows SDK download.


Jon