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3.9 Additional Porting Notes

The configure and build system should work on any system which has a modern "sh" shell, "make", and so on. The configure and build system is less portable than the "C" code itself, however. You may run into problems with the "include" syntax in the Makefiles. You can use GNU make to overcome this, or simply manually include the specified files after running configure.

Instruction for building netCDF on other platforms can be found at http://www.unidata.ucar.edu/software/netcdf/other-builds.html. If you build netCDF on a new platform, please send your environment variables and any other important notes to support@unidata.ucar.edu and we will add the information to the other builds page, with a credit to you.

If you can't run the configure script, you will need to create config.h and fortran/nfconfig.inc. Start with ncconfig.in and fortran/nfconfig.in and set the defines as appropriate for your system.

Operating system dependency is isolated in the "ncio" module. We provide two versions. posixio.c uses POSIX system calls like "open()", "read()" and "write(). ffio.c uses a special library available on CRAY systems. You could create other versions for different operating systems. The program "t_ncio.c" can be used as a simple test of this layer.

Note that we have not had a Cray to test on for some time. In particular, large file support is not tested with ffio.c.

Numerical representation dependency is isolated in the "ncx" module. As supplied, ncx.m4 (ncx.c) supports IEEE floating point representation, VAX floating point, and CRAY floating point. BIG_ENDIAN vs LITTLE_ENDIAN is handled, as well as various sizes of "int", "short", and "long". We assume, however, that a "char" is eight bits.

There is a separate implementation of the ncx interface available as ncx_cray.c which contains optimizations for CRAY vector architectures. Move the generic ncx.c out of the way and rename ncx_cray.c to ncx.c to use this module. By default, this module does not use the IEG2CRAY and CRAY2IEG library calls. When compiled with aggressive in-lining and optimization, it provides equivalent functionality with comparable speed and clearer error semantics. If you wish to use the IEG library functions, compile this module with -DUSE_IEG.
 
 
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