[petsc-dev] Disabling a header in configure based on a bad link?

[Satish Balay]

perhaps the appropriate thing is to move the 'fenv.h' from the current
location to this new test into config/BuildSystem/config/headers.py
[i.e this code would add fenv.h header if the test is successful]

Satish

On Wed, 25 Sep 2013, Aron Ahmadia wrote:

> Hi folks,
> 
> I'm working on a Cygwin64 port of PETSc and I have a question about doing a
> specific disable in BuildSystem based on a failing link.
> 
> The Cygwin folks provide an fenv.h implementation that (as far as I can
> tell), is currently broken due to an undefined FE_DFL_ENV variable.  My
> inclination is to disable this functionality in PETSc by declaring that
> fenv.h is unavailable if a simple link test fails.  I tried to write a test
> like this (in Configure.py)
> 
> def configureCygwin(self):
>   '''Cygwin specific stuff'''
>   # detect problem with missing FE_DFL_ENV symbol in Cygwin64
>   if not self.checkLink('#include <fenv.h>', 'fesetenv(FE_DFL_ENV)'):
>       self.headers.headers.remove('fenv.h')
> 
> 
> I don't think it worked.  Has anybody had experience with *disabling*
> functionality in BuildSystem?  Should we be less optimistic about having
> the header and only enable it if the test passes?  Where would it go?
> 
> Cheers,
> Aron
>