[CMake] Post-Build commands on custom targets are always executed?

[Oliver Buchtala]

Am 18.04.2011 06:58, schrieb Michael Hertling:
> On 04/16/2011 12:05 AM, Oliver Buchtala wrote:
>> Am 15.04.2011 23:48, schrieb Michael Hertling:
>>> On 04/15/2011 11:22 PM, Oliver Buchtala wrote:
>>>> Hi,
>>>>
>>>> I observe that a custom command attached to a custom target as
>>>> POST-BUILD is launched on every build.
>>>> Is that true? or is it a misconfiguration on my side?
>>>>
>>>> Bye,
>>>> Oliver
>>> A custom target is always out of date, i.e. it is always rebuilt when
>>> it is visited - as a prerequisite of another target or due to the ALL
>>> clause, e.g., and since the target has been rebuilt, each associated
>>> POST_BUILD custom command is rerun. Thus, the behaviour you observed
>>> is correct, expected and reasonable, IMO.
>>>
>>> Regards,
>>>
>>> Michael
>> Yep. That's reasonable.
>>
>> Do have a suggestion how to get around a rerun of the post-build?
> Prevent the custom target from being visited, i.e. from being checked
> if it's up to date since it will be found to be out of date, so the
> immediately associated commands - if any - are run as well as the
> associated POST_BUILD custom commands.
>
>> Or how would you do a post-build after custom-target without being run
>> when custom-target actually did nothing,
> What do you mean with a custom target that "actually did nothing"? Not
> visited or no own commands? In the former case, the associated custom
> commands are not run, of course, but in the latter case, it does not
> matter if there are immediately associated commands or not since the
> target will be considered as out of date and rebuilt-without-op, and
> its POST_BUILD custom commands will be run. In other words: A custom
> target - even without own commands - is not good for preventing its
> custom commands from being run when the custom target is visited.
>
>> i.e., custom target depends on custom command that did nothing?
> The same holds for this kind of dependency, i.e. the visited custom
> target will be rebuilt regardless whether the prerequisite custom
> command did do something or not, or do you still talk about the
> custom-command-associated-with-custom-target dependency?
>
Alright. Then, no way to get what i want with custom targets.

I am asking, as I try to improve behavior with UseJave.cmake::add_jar
(on stage::next) which creates a custom target.
E.g., after building the jar I want to copy the java archive into
another destination (not install).
As long as java support is on a weak basis (i.e., not built-in), this
won't change...

Thank you for your help!

Bye,
Oliver