On Sun, Jun 7, 2009 at 3:12 PM, David Bateman<dbate...@dbateman.org> wrote: > Alexander Barth wrote: >> >> On Fri, Jun 5, 2009 at 9:20 PM, David Bateman<dbate...@dbateman.org> >> wrote: >> >>> >>> Why not just use >>> octave_idx_type if the fortran logical index is 8bit with --enable-64? >>> >>> >> >> This is in the end what I did, but I declared a macro >> octave_f77_bool_type defined as octave_idx_type. >> >> The underlying assumption is that the Fortran compiler uses the same >> amount of bytes for INTEGER and LOGICAL. I would prefer to "hide" this >> assumption behind a macro since there might be some Fortran compilers >> that handle things differently. (After all, it is quite wasteful to >> allocate 8 bytes for a variable with only two states). >> >> I looked a bit around how the different Fortran compilers handle the >> size of LOGICALs. For gfortran (with and without -fdefault-integer-8) >> and ifort (with and without -i8), the size of LOGICALs will always be >> the size of INTEGER. However, with pgf90, the compiler option -i8, >> leaves the size of LOGICALs to 4 bytes. Only the option -i8storage >> allocates 8 bytes for INTEGER and LOGICAL. >> >> This reminds me also a bit of the assumption that size of a pointer >> will always be the same as the size of an int in C. Such assumption is >> the classical problem when porting a program to 64-bit CPU. >> >> Cheers, >> Alex >> > > Grrr, then we need an autoconf test that probes the number of bytes in a > fortran logical type and sets your macro appropriately... > > D.
Do we? In fact, I think the Fortran standard requires the default REAL, INTEGER and LOGICAL to be of equal size (numeric storage unit). So, only some combinations of these flags are conforming in general. I do not think Octave needs to be bulletproof in this regard, at least not until a real need arises from practice. When you're altering the sizes of default types, you're often breaking standard-conformance, and you're therefore supposed to know what you're doing. Anyway, a common practical advice is to avoid LOGICALs in external interfaces at all and just use INTEGERs. cheers -- RNDr. Jaroslav Hajek computing expert & GNU Octave developer Aeronautical Research and Test Institute (VZLU) Prague, Czech Republic url: www.highegg.matfyz.cz ------------------------------------------------------------------------------ OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get _______________________________________________ Octave-dev mailing list Octave-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/octave-dev
