On Wed, Jan 2, 2013 at 12:09 PM, Dmitri Gribenko <[email protected]>wrote:

Sorry if what I wrote was unclear. Here's a complete example:

$ cat t.cc #include <mpi.h>

enum MyEnum { Foo }; MPI_Datatype MyEnumDatatype MPICH_ATTR_TYPE_TAG(MyEnum);

Oh, fantastic. I didn't realize this could be applied to uninitialized variables (and somehow didn't recognize that you were saying as much in the first email). In light of this, can mpi.h change all the static declarations to extern so that the symbols are guaranteed to only show up once in executables (rather than once per compilation unit)? And yes, I'm aware of the flexibility the standard gives compiler implementers regarding enum size.