Re: [Plplot-devel] Build problems with octave

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

On 2013-12-29 11:18-0700 Orion Poplawski wrote:

> On 12/29/2013 11:00 AM, Alan W. Irwin wrote:
>> [...T]he root cause is a subtle change in how
>> octave attempts to include its config.h.  For 3.6.x, oct.h used
>>
>> #include "config.h"
>>
>> which meant that file (located in the same directory as oct.h for
>> 3.6.x) is always safely found without clashing with other config.h
>> files.  But now I think the Octave developers have made a somewhat
>> irresponsible choice
>> for how they handle config.h for 3.8.0. They changed oct.h (see above)
>> to use the angle-bracket form
>>
>> #include <config.h>
>>
>> which means the compiler is allowed to look everywhere for config.h
>> that is allowed by the -I switch order which is much less safe against
>> name clashes (e.g., with PLplot's config.h) and also now requires two -I
>> switches to find all the Octave headers assuming the new location of
>> config.h is /usr/include/octave-3.8.0 rather than
>> /usr/include/octave-3.8.0/octave.
>
> Ah, good catch, that may be the issue.  I've filed:
> https://savannah.gnu.org/bugs/index.php?41027
>
>>
>> <aside>
>> Both above and below your -I switches point to _both_
>> /usr/include/octave-3.8.0/ and /usr/include/octave-3.8.0/octave which
>> suggests the new location (for 3.8.0) for config.h might be
>> /usr/include/octave-3.8.0/.  (Note on my Debian stable system
>> /usr/include/octave-3.6.2/ has nothing in it but the octave subdirectory
>> so there is no need for those two different -I switches.)
>> </aside>
>>
>
> The issue is that octave using programs use <octave/oct.h> but the
> octave headers just use "oct.h".
>
>>>
>>> /usr/bin/c++   -DHAVE_CONFIG_H -Dplplot_octave_EXPORTS -O2 -g -pipe
>>> -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
>>> -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches
>>> -m32 -march=i686 -mtune=atom -fasynchronous-unwind-tables  -fPIC
>>> -I/builddir/build/BUILD/plplot-5.9.10/include
>>> -I/builddir/build/BUILD/plplot-5.9.10/lib/qsastime
>>> -I/builddir/build/BUILD/plplot-5.9.10/fedora
>>> -I/builddir/build/BUILD/plplot-5.9.10/fedora/include
>>> -I/builddir/build/BUILD/plplot-5.9.10/fedora/bindings/octave
>>> -I/usr/include/octave-3.8.0 -I/usr/include/octave-3.8.0/octave
>>> -I/builddir/build/BUILD/plplot-5.9.10/bindings/swig-support    -o
>>> CMakeFiles/plplot_octave.dir/plplot_octaveOCTAVE_wrap.cxx.o -c
>>> /builddir/build/BUILD/plplot-5.9.10/fedora/bindings/octave/plplot_octaveOCTAVE_wrap.cxx
>>>
>>> In file included from /usr/include/octave-3.8.0/octave/dim-vector.h:35:0,
>>>                 from /usr/include/octave-3.8.0/octave/Array.h:35,
>>>                 from /usr/include/octave-3.8.0/octave/boolMatrix.h:27,
>>>                 from /usr/include/octave-3.8.0/octave/mx-base.h:32,
>>>                 from /usr/include/octave-3.8.0/octave/Matrix.h:30,
>>>                 from /usr/include/octave-3.8.0/octave/oct.h:33,
>>>                 from
>>> /builddir/build/BUILD/plplot-5.9.10/fedora/bindings/octave/plplot_octaveOCTAVE_wrap.cxx:154:
>>>
>>> /usr/include/octave-3.8.0/octave/oct-refcount.h:27:3: error: #error "The
>>> file <octave/config.h> must be included before oct-refcount.h."
>>> # error "The file <octave/config.h> must be included before
>>> oct-refcount.h."
>>>   ^
>>
>> I frankly don't understand how the above is finding PLplot's config.h
>> which should be located in the top directory of the build tree which I
>> infer is /builddir/build/BUILD/plplot-5.9.10 in the above case.  But
>> none of the above
>> -I switches point to that location.  So I may be missing something.  But
>> if -I/builddir/build/BUILD/plplot-5.9.10 came before
>> -I/usr/include/octave-3.8.0, then the compiler would pick the Plplot
>> version of config.h to use for both PLplot and octave, and if the order
>> were reversed, the compiler would pick the Octave version of config.h
>> to use for both PLplot and octave.
>
> Perhaps it could be some other config.h?

The above -I options include nothing but PLplot build tree and Octave
locations.  I guess there is always a change a default system header
location (also checked by gcc) on Fedora could contain a config.h file,
but I assume that is unlikely.

Please let me know if my latest PLplot change from config.h to
plplot_config.h (revision 12914) solves this issue. Of course, if it
doesn't solve it, the change was worth doing anyway. And if it does
solve it, I hope your bug report still convinces the Octave developers
to move back to using the quoted form of #include for config.h (or
better yet change the name to octave_config.h). After all, there are
likely quite a few software projects still left out there that do use
the config.h name (at least internally in their build tree as PLplot
did up to now).

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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