From: rusrabe@XXXXXXXXXXXXXXXXXXXXXXXXXX
Subject: Re: clarification on inter-language interoperability of attributes
To: snir@XXXXXXXXXX
Date: Fri, 26 Mar 1999 09:53:40 +0100 (MEZ)
Cc: nevin@XXXXXXXXXXXXXXXXX,mpi-core@XXXXXXXXXXX
In-Reply-To: <8525673F.0080699E.00@XXXXXXXXXXXXXXXXXXXX>
Content-Type: text
Sender: owner-mpi-core@XXXXXXXXXXX
Precedence: bulk
X-UIDL: f62bf11b26729f31fec984011630bb21

Nick Nevin mentioned:
>  MPI_Comm_get_attr(MPI_COMM_WORLD, MPI_TAG_UB, &tagub, &flag);
                                     ========== 
 
Marc Snir stated:
> It's a bad idea to store and retrieve integer attributes in C -- since C stores
> and retrieves attributes of type void* (pointers). You can either
                                                         ========== 
[...] 
> int ub;
>    MPI_Comm_put_attr(..., (void*)ub,...);
[or] 
> int ub;
> int *tagub
>    *tagub = ub;
>    MPI_Comm_put_attr(..., tagub,...);

But MPI 1.1 has defined 4 predefined INTEGER/int-typed attributes
in the "7.1.1 Environmental Inquiries", and therefore,
the question is, which "MPI_Comm_put_attr" is done by
all MPI implementations.
===

Rolf 

PS: I have no opinion, what is the right answer, but when it will
    be clear, it would be nice, if we add as clarification
    an example, how to use MPI_Comm_get_attr with the 
    predefined valus in Fortran and C.