[CMake] Executing python though CMake and linking libraries

[Kit Chambers]

I just got this working, so am posting to the list in case this helps someone else in the future. Essentially you invoke the python script through CMakes -E command and specify your library paths so it picks up all your shared libraries. Something like:

add_custom_target(run
               COMMAND cmake "-E" "env"  “LD_LIBRARY_PATH=/your/library/path DYLD_LIBRARY_PATH=/library/path/for/mac/" “python” “./myscript.py”
		WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
                ) 

However, I will be the first to admit this is not a particularly elegant solution so I would be interested to here if anyone out there has a better way of getting invoked commands to pick up the environment paths correctly.

Kit




> On 25 Nov 2016, at 13:23, tonka3100 at gmail.com wrote:
> 
> Hey,
> 
> I think your actual working directory is wrong. I would recommend to use absolute paths for the python interperter (there is a find_package module for the interpreter) and maybe also for your script. The custom command support a workingdirectory variable as far as i know.
> 
> Hope that help you.
> 
> Greetings
> Tonka
> 
>> Am 25.11.2016 um 10:04 schrieb Kit Chambers <kit.chambers.kc at gmail.com>:
>> 
>> I have a Cmake custom target which runs a python script:
>> 
>> add_custom_target(run
>>                COMMAND python myscript.py
>>                 ) 
>> 
>> And the script myscript.py imports a Compiled library 
>> 
>> import myproj.mylilb
>> 
>> where mylib is actually a C++ library generated with python bindings (using vtkPython). This intern links against some other C++ libraries I use etc.
>> 
>> 
>> When I run the script normally from the command line everything works fine, but if I try to run the target I get linker errors.
>> 
>> $ make run
>> 
>> Traceback (most recent call last):
>> File "myscript.py", line 8, in <module>
>>  import myproj.mylilb
>> ImportError: dlopen(/Users/kitchambers/Applications/ogFramework/lib/python2.7/site-packages/myproj/mylib.so, 2): Library not loaded: libSpProcSupport.so
>> Referenced from: /Users/kitchambers/Applications/ogFramework/lib/python2.7/site-packages/myproj/mylib.so
>> Reason: image not found
>> 
>> To me it looks like my LD_LIBRARY_PATH and DYLD_LIBRARY_PATH are not being passed through CMake to Python so it cannot find all the necessary sub libraries. However, i cannot work out how to pass this information through.
>> 
>> Any help would be greatly appreciated.
>> 
>> Cheers
>> 
>> Kit
>> -- 
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