[cmake-developers] Should a module attempt to find its own dependencies?

[Michael Wild]

On 01/09/2012 03:07 AM, David Cole wrote:
> 
> 
> On Sunday, January 8, 2012, Alexander Neundorf <neundorf at kde.org
> <mailto:neundorf at kde.org>> wrote:
>> On Sunday 08 January 2012, Stephen Kelly wrote:
>>> Alexander Neundorf wrote:
>>> > On Sunday 08 January 2012, Stephen Kelly wrote:
>>> >> Hi,
>>> >>
>>> >> I don't think I've ever seen a direct answer to this question.
>>> >
>>> > AFAIK, yes, they should.
>>> > FindKDE4Internal.cmake finds Qt, FindPNG.cmake finds zlib.
>>> >
>>> >> Is it something to be decided on a case by case basis? If so, then why
>>> >> is there no general case?
>>> >>
>>> >> I can see a possible reason that it is not solvable in the general
> case
>>> >> because sometimes the behaviour of find_package can be changed by
>>> >> setting variables (eg, one might use QT_USE_QTXMLPATTERNS before
>>> >> finding Qt4).
>>> >>
>>> >> Specifically this comes up for me because I need to know whether Qt5
>>> >> modules should find their own dependencies. That is, should
>>> >>
>>> >> find_package(Qt5Gui)
>>> >>
>>> >> cause
>>> >>
>>> >> find_package(Qt5Core REQUIRED)
>>> >>
>>> >> to be called or not?
>>> >
>>> > I'd say yes.
>>> > Otherwise the imported targets in Qt5Gui will depend on not yet defined
>>> > targets from Qt5Core.
>>> >
>>> > The same way cmake takes care of adding the required additional
> libraries
>>> > to the link line (like adding zlib when linking libpng), it should also
>>> > take care of this, IMO.
>>> >
>>> > You should just have to state
>>> > find_package(Foo)
>>> > and this will get you Foo.
>>>
>>> That implies that
>>>
>>> * Qt5Gui_INCLUDE_DIRS should also contain Qt5Core_INCLUDE_DIRS
>>>
>>> * Qt5Gui_DEFINITIONS should contain Qt5Core_DEFINITIONS
>>>
>>> * Qt5Gui_COMPILE_DEFINITIONS should contain Qt5Core_COMPILE_DEFINITIONS
>>>
>>> Right?
>>
>>
>> Yes, I'd say so.
>> But let's wait also for some opinions from others.
>>
>> Alex
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> 
> I'd say so too. Waiting for a dissenting opinion... ;-)

Not from me... I fully agree with Alex.

Michael