Re: Packaging Octave for Windows and OS X (was: writing integer with fwrite)

[John W. Eaton]

On 14-Dec-2004, Paul Thomas <address@hidden> wrote:

| Dear All,
| 
| > My understanding is that this is due to the way exception handling is
| > implemented in GCC 3.3 for Cygwin.  Does anyone know whether this is
| > likely to improve any time soon?  Long term, we need to support
| > improving the compiler.
| >
| I am still in sporadic communication with the gcc developers about this.
| 
| I had an attempt at building octave with gcc-4.0.0 somewhile back.  It 
| bombed out because of clashes between the new fortran library and libm, 
| amongst others.  I left it at that point, thinking that this is something 
| that will get straightened out in time.  I therefore did not push on to test 
| build the c++ libraries.  It was something of a surprise, therefore, when I 
| repeated some of the new/delete tests with g++-4.0.0 and found that the 
| slowness has gone away.  Nobody has explained it yet but I suspect that I am 
| getting dwarf2 as a default, rather than -sjlj.  It might, therefore be 
| worth either fixing the libgfortran/libm clashes or using g77-3.4.x, instead 
| of gfortran.

OK, at least it looks like your initial report has received some
attention.  I see the following thread:

  http://gcc.gnu.org/ml/gcc-patches/2004-11/msg01989.html

so maybe this will be fixed at some point, but perhaps not in time for
GCC 4.0.

Reading some other messages, it appears that it is not as though
Dwarf2 exception handling does not work at all, but that there is some
problem with that EH model in combination with Windows callbacks when
using the MinGW compiler.  Reverting to SJLJ EH was a quick fix.  But
if you wanted to, it seems you could build the current GCC with Dwarf2
EH enabled, at least for building Octave.  Does that not work?

jwe



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