[petsc-dev] [petsc-maint #49590] problem building petsc-dev

[Barry Smith]

   Hmm, maybe we should just require users to use --with-pic if they want to do shared libraries. 

   The other choice is to remove --with-pic completely and automatically look for pic flags ONLY if --with-shared is turned on?

   Both match our standards; BUT --with-pic is a pain to always have to type in and it would be rare that one wants --with-pic but not --with-shared

   Barry

On Jul 16, 2010, at 9:09 PM, Satish Balay wrote:

> The previous change to pic default had this comment. [And this change
> must have been done form some other petsc-maint issue. And I keep
> forgetting senarios/issues when this was done]
> 
>>>>>> 
> 5a0c830b3a17
>    -defaut pic=0 [shared=0]
>    - do pic check only when shared=1 or pic=1
>    - special pic check for borland is removed - as its no longer required for shared=0 [default]
> <<<<<
> 
> So the primary issue with default-pic=1 is: its contradictary to
> default-shared=0. [and will be tempted to rectify this contradiction a
> couple of years from now again]
> 
> Satish
> 
> On Fri, 16 Jul 2010, Barry Smith wrote:
> 
>> 
>>  Hmmm, I never use --with-pic=1 
>> 
>>  Why don't we just enable pic by default. Then if user does --with-pic=0 --with-shared we complain. Better than always required shared people to use --with-pic. People who don't want to use --with-pic are far and few between.
> 
> 
>> 
>>    Barry
>> 
>> On Jul 16, 2010, at 8:39 PM, Satish Balay wrote:
>> 
>>> On Fri, 16 Jul 2010, Barry Smith wrote:
>>> 
>>>> 
>>>> I think Satish is right we should have
>>>> 
>>>> --with-shared-libraries
>>>> --with-dynamic-loading 
>>>> 
>>>> I haven't made this change but I've changed
>>>> 
>>>> improved help message for --with-shared	and --with-dynamic
>>>> made --with-dynamic require --with-shared
>>>> make --with-shared NOT allow --with-pic=0
>>> 
>>> Barry,
>>> 
>>> With this change one has to always do the following for sharedlibs:
>>> 
>>> --with-pic=1 --with-shared=1
>>> 
>>> and for dynamic libraries.
>>> 
>>> --with-pic=1 --with-shared=1 --with-dynamic=1
>>> 
>>> Earlier behavior was for --with-pic to be implicitly enabled for
>>> with-shared or with-dynamic. It would be good to retain the old
>>> behavior.
>>> 
>>> Part of the problem is: configure cannot distinguish between user
>>> provided value vs configure default value - for any given option. So
>>> we can't do both:
>>> 
>>> * default-pic=disabled but  autoenable if  user provides --with-shared=1
>>> * if user provides '--with-pic=0 --with-shared=1' - flag as error.
>>> 
>>> [I didn't remember this part - when I started this thread about this
>>> issue. Looks like we should silently ignore --with-pic - when
>>> --with-shared is enabled]
>>> 
>>> Satish
>>> 
>>> 
>>>> I'll change the option names in a little while
>> 
>> 
>