[mpich-devel] Weak symbols, clang, and users compiling with -fvisibility=hidden

[Jed Brown]

Jed Brown <jedbrown at mcs.anl.gov> writes:

> Pavan Balaji <balaji at mcs.anl.gov> writes:
>> This attribute is tested in configure before it’s added to mpi.h.in.
>
> Yes, the configure test is incorrect and the resulting usage in MPICH is
> broken (does not do what you intend).

As far as I know,

  #pragma weak MPI_Xyz = PMPI_Xyz

is equivalent to what was intended with the attribute syntax

  __attribute__((weak, alias("PMPI_Xyz")))

(which belongs in an implementation file, not in the public header).  Is
there a reason to bother testing for the attribute syntax?
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