[MPI3 Fortran] Fwd: [Mpi-comments] MPI 3.0: Fortran 2008 interface - issue with the LOGICAL kind

Malcolm Cohen malcolm at nag-j.co.jp
Fri Mar 1 03:06:50 CST 2013

Bill Long writes:
>The value of C_BOOL as a Fortran KIND type for LOGICAL is such that
>1) The bitsize of LOGICAL(C_BOOL) matches the bitsize of _Bool in C for the 
>companion processor.
>2) The Fortran processor uses the internal bit pattern in LOGICAL (C_BOOL) of 0 
>to represent false, and 1 to represent true.

Nick Maclaren asks:
>Does it?  I can't find that in the Fortran standard.  Either I have
>missed it, or this is a wart that we should consider for the next

I think this is inherent in the meaning of the word "interoperable": if the 
internal representation is different, it cannot interoperate (though we fudged 
that with unsigned...).  This could be clarified editorially in the next 

................................Malcolm Cohen, Nihon NAG, Tokyo. 

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