[CMake] Fwd: how do I test if a library target is static or shared?

Tue Sep 23 15:03:10 EDT 2008

I think in the end I'll replace my ADD_SUBDIRECTORY+macros[1] method
for a simpler INCLUDE based ones. The INCLUDE based one isn't ideal
(and really, it seems like an abuse of INCLUDE for something
ADD_SUBDIRECTORY or EXPORT should do), but its less code and more
natural to cmake users.

Thanks for your help.

[1] here's an example of my I_* macros... I'll be switching this over
to INCLUDEs though:
http://labs.wexussoftware.com/cgi-bin/git.cgi?p=scopira.git;a=blob;h=35a96306ca05a4415d1caf06067cd33660cbd471;hb=abb1d7823969b4104e3bdf8ac4d9853b041cc14f;f=scopira.src/CMakeLists.txt

On Tue, Sep 23, 2008 at 12:15 PM, Mike Jackson
<mike.jackson at bluequartz.net> wrote:
> That is basically what I do. Until someone tells me a better way.
>
> Take a look at the following link:
>
> http://www.bluequartz.net/viewvc/CTMD/MXATools/CMakeLists.txt?view=markup
> for an example of how I am doing things.
>
> mike
>
> Aleksander Demko wrote:
>>
>> I guess I'm looking for a way to automatically "relay" information
>> between the main project B and one or more library projects A, etc. My
>> projects tend to involve lots of sub libraries, so I need a way for
>> this to work in a scalable manner.
>>
>> If I try to simply INCLUDE A in B, then all the relative source paths
>> in the add_library call do not work. Is there a nice work around for
>> this?
>>
>> My current solution involves that I, in executable B, do an
>> ADD_SUBDIRECTORY on A. I then have a few (gross) macros that help me
>> propagate the include dirs and defines in A up to B. The macros
>> inspect and manipulate the COMPILE_FLAGS properties of the targets.
>> Here is a short example (my macros are named I_*):
>>
>> ...
>> ADD_SUBDIRECTORY(${DBA_SRC_PATH} dba)
>> ...
>> ADD_LIBRARY(wxdba wxdba/colour_fi...
>> I_ADD_RELATIVE_INCLUDE(wxdba .)
>> I_TARGET_LINK_LIBRARY(wxdba dba)
>> I_ADD_COMPILE_FLAGS(wxdba /DwxUSE_UNICODE)
>>
>> Then sub executables can use wxdba and include all the cflags, include
>> directories needed for both wxdba and its dependent project dba. The
>> wxdba project also inherited any cflags/include directories that dba
>> had via the I_TARGET... call.
>>
>> I was hoping for a more mainstream approach that requires less
>> specialized macros.
>>
>> On Mon, Sep 22, 2008 at 7:41 PM, Mike Jackson
>> <mike.jackson at bluequartz.net> wrote:
>>
>>>
>>> Not totally sure what you are after BUT one possible implementation is
>>> something like the following.
>>>
>>> If you have a Library A that you want to include in Executable B and Both
>>> are there own projects based on CMake then there is "some" integration
>>> that
>>> can happen.
>>>
>>> So for library A you have a normal CMakeLists.txt file for that project.
>>> Then for the executable project you simply "include" the CMakeLists.txt
>>> file
>>> from library A.
>>>
>>> If the "Library A" project you have:
>>> add_library (A SHARED ${sources})
>>>
>>> Then in the executable project you have something like:
>>>
>>> add_executable (myexec ${sources} )
>>> target_link_libraries(myexec A)
>>>
>>> When you build the executable project CMake will automatically build the
>>> "A"
>>> library first. This is one way to achieve this. ( I do this in a few of
>>> my
>>> projects ).
>>>
>>>
>>>
>>> Some helper code that might be handy:
>>> # This code goes in the Executable projects CMakeLists.txt file
>>> # --- Get the LibA Project by looking for a folder called "src" in the
>>> LibraryA folder
>>> GET_FILENAME_COMPONENT(CURRENT_SOURCE_PARENT ${CMAKE_CURRENT_SOURCE_DIR}
>>> PATH)
>>> FIND_PATH(A_SOURCE_DIR src
>>>  "${CURRENT_SOURCE_PARENT}/LibraryA"
>>> )
>>> IF (NOT A_SOURCE_DIR)
>>>   MESSAGE(FATAL_ERROR "Could not find LibraryA Directory. Please set the
>>> directory")
>>> ENDIF(NOT MXA_SOURCE_DIR)
>>>
>>> Now. if you can not do something like the above or you don't want to tie
>>> the
>>> projects together like that then you can "configure" a header file from
>>> LibraryA that can be used in the executable project to "relay"
>>> information
>>> about the library, like if it was built as a shared or static library.
>>> Again, this is also done in lots of projects.
>>>
>>> The last way to "relay" information would be to have CMake write the
>>> information into a simple text file that the executable project can then
>>> parse.
>>>
>>> Keep asking.. we'll help as much as we can.
>>> ---
>>> Mike Jackson - Principal Software Engineer
>>> www.bluequartz.net
>>>
>>>
>>>
>>>
>>> On Sep 22, 2008, at 5:46 PM, Aleksander Demko wrote:
>>>
>>>
>>>>
>>>> Dang, that won't work for me. I'm in effect trying to make my own
>>>> EXPORT like command (export doesn't maintain C flags or other stuff I
>>>> need) so I need to be able to gleam a bunch of info from the library
>>>> targets dynamically.
>>>>
>>>> Basically I want to quickly build one library in one cmake session,
>>>> than import it in another (without have to write custom Find-.cmake
>>>> files etc). Maybe this exists already in cmake, but I can't seem to
>>>> find it.
>>>>
>>>>
>>>> On Mon, Sep 22, 2008 at 4:32 PM, Mike Jackson
>>>> <mike.jackson at bluequartz.net> wrote:
>>>>
>>>>>
>>>>> You will probably have to set your own variable into the cache and then
>>>>> check that variable later on in your scripts
>>>>>
>>>>>
>>>>>
>>>>> On Sep 22, 2008, at 5:23 PM, Aleksander Demko wrote:
>>>>>
>>>>>
>>>>>>
>>>>>> On Mon, Sep 22, 2008 at 4:15 PM, Mike Jackson
>>>>>> <mike.jackson at bluequartz.net> wrote:
>>>>>>
>>>>>>>
>>>>>>> Assuming you mean a library that you are creating the default is
>>>>>>> static.
>>>>>>> If
>>>>>>> you want a dynamic library then use the "SHARED" keyword:
>>>>>>>
>>>>>>> add_library (mylib SHARED libsource.cpp)
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> I understand that. But later in my script I want to check if mylib is
>>>>>> shared or static with an IF command. I want the command to know if the
>>>>>> add_library was the default static, shared or shared because
>>>>>> BUILD_SHARE_LIBS is true.
>>>>>>
>>>>
>
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