[ros-dev] __attribute__((weak)) - in mingw

[Danny Smith]

Boaz Harrosh wrote:
> [Q] I'm (well ATL is) using  __attribute__((weak)) (translated from
> __declspec( selectany) ) for instantiation of members and variables in
> headers. I had no problem with it On GCC in Linux (gcc 3.2.2). On MinGW

IMAGE_COMDAT_SELECT_ANY is not quite same as PECOFF version of "weak" , but
AFAICT is equivalent to the GCC section flag ".linkonce discard".  I don't think
there is a way for the user to specify that for data using an attribute, but it
could be done with asm statements.

.weak directive is partially supported in current binutils CVS.
__attribute__((weak)) is not supported by GCC-3.4.x but will be in the next
major GCC release (4.0.0).

The semantics of weak for PECOFF differ from that on Linux.See the PECOFF60
specs (Microsoft Portable Executable and Common Object File Format
Specification)  section on weak externals

Danny