[Mpi-forum] Preprocessor Constants

N.M. Maclaren nmm1 at cam.ac.uk
Tue Nov 23 03:52:42 CST 2010

On Nov 23 2010, Hal Finkel wrote:
>> As noted in New Orleans, you have a bit of a challenge with this idea 
>> in that some vendor MPI implementations do not use wrapper compilers, 
>> and therefore may have some difficulty in providing this macro. ...

Boggle.  Not that all don't use wrapper compilers - I know that - but
that they might have difficulty.

>My personal experience is limited to two kinds of MPI implementations:
> 1. An implementation which provides wrapper scripts (i.e. mpicc). These 
> scripts could easily add -D_MPI would prevent the conforming use of 
> POSIX! See:

    2.2 The Compilation Environment
        2.2.1 POSIX.1 Symbols
>2. An implementation which simply documents the flags necessary for
>compiling and linking. ...

Add: 3. An implementation that uses a pre-processor.

In all cases, adding such a macro is trivial.  While it is certainly
possible to imaging a C environment that can add headers but not macros,
it's implausible, to put it mildly.

Nick Maclaren.

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