[CMake] How to describe lib dependencies when a lib has different possible implementations?

[Christopher Harvey]

oh I see. I thought the problem was that you didn't want to physically 
type out all that information.

Michael Jackson wrote:
> Not sure you want to go down this path but the CMake files in the SVN 
> repository of Boost has some facilities to figuring out dependencies 
> through a chain like you have. Basically what the boost authors have 
> created are some macros that allow you to add a library/executable and 
> declare only the top most dependency. That dependency then figures out 
> what it needs, and so on down the line. We were actually able to adapt 
> the code to output a dependency graph that could be rendered with 
> graphViz (.dot file).
>   It almost sounds like you need something similar for your project. 
> The boost code is open-source so you might be able to pick and choose 
> what you need/want.
>
>   You could also build up lists of the dependencies for each library, 
> then tack those dependencies onto the next library up although that 
> might get pretty complicated pretty quick with the amount of libraries 
> that you have.
>
> ---
> Mike Jackson                 www.bluequartz.net
>
>
>
> On Mar 19, 2009, at 2:33 PM, Alexandre Feblot wrote:
>
>> Hum,
>> I don't see what you mean. In the cmake spirit, my executable don't 
>> even know they will depend on lib4. exe1 just knows it depends on 
>> lib1. Then lib1 just knows it depends on lib3. Then, lib3 just knows 
>> it depends on lib4, i.e. lib4-A to build exe1-A and lib4-B to build 
>> exe1-B. (and in the real situation, there is not only one of these 
>> "dual" libraries, and the dependency chain is too complicated for us 
>> to keep maintaining it by hand).
>>
>>
>>
>> Alexandre
>>
>> -----Message d'origine-----
>> De : cmake-bounces at cmake.org De la part de Christopher Harvey
>> Envoyé : jeudi 19 mars 2009 19:04
>> À : Alexandre Feblot
>> Cc : cmake at cmake.org
>> Objet : Re: [CMake] How to describe lib dependencies when a lib has 
>> different possible implementations?
>>
>> If you want to compile two execs, one for each static library you can
>> use a two element list and go "for_each" over each library and create
>> two execs. Otherwise you can just hardcode it into cmake.
>>
>> Alexandre Feblot wrote:
>>>
>>> Hi,
>>>
>>> in fact, in my current system, the implementation to use is pretty 
>>> hardcoded in each executable makefile, in the link line. There is no 
>>> automatic lib dependency management.
>>>
>>>
>>> Alexandre
>>>
>>> -----Message d'origine-----
>>> De : cmake-bounces at cmake.org De la part de Christopher Harvey
>>> Envoyé : jeudi 19 mars 2009 17:58
>>>
>>> Hi,
>>> Interesting question. You said that
>>> "only one of them has to be used in every executable, the 
>>> implementation
>>> to use is determined by the executable."
>>> These are static libraries, so how can the exec pick one if it isn't
>>> even built? (As opposed to loading one dynamically)
>>> Basically I'm still wondering at what point you want the decision for
>>> one of the two libraries to made and how you make that decision.
>>> How exactly did you do it beforehand, without cmake?
>>> CMake has IF statements, so I'm pretty sure it'll be no problem just
>>> have no idea what you would put in those ifs.
>>>
>>> Chris.
>>>
>>> Alexandre Feblot wrote:
>>>
>>>> Hi,
>>>>
>>>> I'm facing an issue while trying to port my current build system to
>>>> cmake and don't know is there is a way to solve it:
>>>>
>>>> In our project, we build a bunch of *static* libs (about 360) and
>>>> several executables on them.
>>>>
>>>> * one library, in the middle of the lib dependency chain, has in fact
>>>> 2 different implementations. That is to say, there are 2 different
>>>> libs with the exact same interface, but they don't use the same
>>>> back-end, have different source code, and don't have the same
>>>> dependencies.
>>>> * only one of them has to be used in every executable,
>>>> the implementation to use is determined by the executable.
>>>>
>>>> Dependency graph example: "->" means "depends on"
>>>>
>>>> *exe1-A* -> lib1 -> lib3 -> *lib4-A* -> lib5 -> lib7
>>>> *exe1-B* -> lib1 -> lib3 -> *lib4-B* -> lib6 -> lib8
>>>> *exe2-A* -> lib2 -> lib3 -> *lib4-A* -> lib5 -> lib7
>>>> *exe2-B* -> lib2 -> lib3 -> *lib4-B* -> lib6 -> lib8
>>>>
>>>>
>>>> I'd like to keep using the standard cmake mechanism of dependency
>>>> description in which every lib only defines on which other libs it
>>>> depends, and let cmake compute the final link line.
>>>>
>>>> The question is: how can I express the dependencie of lib3 on
>>>> lib4 whereas lib3 has only a single description, and we don't know
>>>> when describing it, if we'll have to use lib4-A or lib4-B. (and
>>>> anyway, depending on the executable, we'll have to use each of them).
>>>>
>>>> Is there any concept of "abstract" target (lib4 in my example) which
>>>> could be "instanciated" in the executable description (as lib4-A or
>>>> lib4-B in the example)
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Alexandre
>>>>
>>>>
>>>> This email was sent to you by Thomson Reuters, the global news and
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>>>> Any views expressed in this message are those of the individual
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>>>> views of Thomson Reuters.
>>>>
>>>>
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