2.9 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.
If you can't run the configure script, you will need to create
libsrc/ncconfig.h and fortran/nfconfig.inc. Start with
libsrc/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.
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.
