-malign-double

[Barry Smith]

    What about have configure look for uintptr_t  if it does not exist  
then have configure check if unsigned long long is large enough, if  
not try size_t otherwise barf?

    Barry

On Nov 16, 2009, at 1:55 PM, Jed Brown wrote:

> Barry Smith wrote:
>>
>>  Jed,
>>
>>   Seems ok to me. Feel free to update PETSc. (But I think PETSc style
>> would detect that your PETSC_ALIGN() macro would be called
>> PetscMemAlign() or something, we only use caps for macros that are  
>> fixed
>> values, not for macros that like functions.)
>
> Indeed (though there are a few exceptions).
>
> Although stdint.h (which contains uintptr_t) is required by C99, I
> suppose it's likely that it's broken somewhere.  On Win64, unsigned  
> long
> is not sufficient so we need unsigned long long (also required by C99,
> but not in C++).  This is messy enough that we may as well work around
> it by truncating the pointer into an unsigned, computing the shift,  
> and
> adding the shift through a (char*) cast.  Please speak up if uintptr_t
> is actually reliable.  (I just require a C99 compiler and don't  
> tolerate
> non-compliance, but PETSc can't do that).
>
> Jed
>