Re: [Plplot-devel] Command-line parsing improvements for both C and Fortran

[Alan W. I. <ir...@be...>]

On 2017-12-27 14:26-0800 Alan W. Irwin wrote:

> Hi Arjen:
>
> I have done some further investigation and it appears that even today
> allocatable character arrays are problematic to a certain extent for
> Fortran compilers. For example, see
> <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80945>. I have no clue
> whether that particular modern gfortran bug would affect us.  However,
> the existence of such bug reports for a modern version of a Fortran
> compiler indicates we should proceed with caution with allocatable
> character arrays.
>
> Therefore, once we implement allocatable character array variants of
> plget_arguments and plparseopts we should survey the modern versions
> of gfortran, ifort, and nagfor to see which of those work well with
> that API.  Also we will likely want to retain the the current static
> assumed shape character arrays API's for those functions for a while
> so that users with access only to older Fortran compilers (e.g.,
> gfortran-4.9.2) that are unreliable with the allocatable character
> array approach have a plget_arguments and plparseopts API that
> they can use.

Hi Arjen:

I have just pushed commit 6f2f4e4 to master which implements dynamic
length and size as well as static length and dynamic size variants of
plget_arguments and plparseopts.  The former does not work with
gfortran-4.9.2, but the latter (as well as the static length and size
variants implemented before) works well.  For more details about how
these tests should be done and results for gfortran-4.9.2, please see
the revised version of README.release section 2.7.2.

This commit completes my parsing API changes in bindings/fortran/*.f90
and my changes to examples/fortran/x01f.f90 to test all of these
parsing API's.  I would appreciate your review of my implementation.
Furthermore, I would appreciate you following the parsing testing
advice in README.release section 2.7.2 to discover which parts of this
API work for gfortran with version > 4.9.2 (e.g., for your Cygwin
and MinGW-w64/MSYS2 platforms) as well as the ifort
compiler you have access to (and possibly the nagfor compiler you have
arranged access to in the past).

By the way, I am not sure of the correct terminology for character
arrays that have both length and size allocated.  I refer to them
above as "dynamic length and size", but I have also seen the
term "deferred-length" used for character strings with allocated
length.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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