[petsc-dev] MPI_UNSIGNED_LONG_LONG in mpiuni.h

[Chetan Jhurani]

> -----Original Message-----
> From: Jed Brown [mailto:five9a2 at gmail.com] On Behalf Of Jed Brown
> Sent: Thursday, April 25, 2013 11:09 AM
> To: Chetan Jhurani; 'For users of the development version of PETSc'
> Subject: Re: [petsc-dev] MPI_UNSIGNED_LONG_LONG in mpiuni.h
> 
> Chetan Jhurani <chetan.jhurani at gmail.com> writes:
> 
> > Hi,
> >
> > mpiuni.h does not define MPI_UNSIGNED_LONG_LONG, which leads
> > to a problem in defining MPIU_SIZE_T here in petscsys.h.
> >
> > #if (PETSC_SIZEOF_SIZE_T) == (PETSC_SIZEOF_INT)
> > #define MPIU_SIZE_T MPI_UNSIGNED
> > #elif  (PETSC_SIZEOF_SIZE_T) == (PETSC_SIZEOF_LONG)
> > #define MPIU_SIZE_T MPI_UNSIGNED_LONG
> > #elif  (PETSC_SIZEOF_SIZE_T) == (PETSC_SIZEOF_LONG_LONG)
> > #define MPIU_SIZE_T MPI_UNSIGNED_LONG_LONG
> 
> mpiuni/mpi.h also has this unguarded statement.  Do all Windows
> compilers now provide 'long long'?
> 
> #define MPI_LONG_LONG_INT    sizeof(long long)
> 
> We could make mpiuni define MPIU_SIZE_T itself instead of jumping
> through hoops to find the matching type.
> 
> Chetan, what's your perspective about using stdint.h?

Info about long long:

Visual Studio 2005 supports long long (sizeof = 8)
even when compiling in 32 bit mode, so I assume all
later ones do.

Trilinos 11.0+ uses long long for 64-bit indices.  I have tested
it with two compilers (2005/2012) and I'm guessing others
have used other versions.

About stdint.h:

I see that it is there with Visual Studio 2012 on
my machine, but not with 2005.  Below is more info
on stdint and MS VS.  I never had a need to use
it so can't say more than this.

http://stackoverflow.com/questions/126279/c99-stdint-h-header-and-ms-visual-studio

Chetan