[CMake] cmake PyQT/SIP

[Michael Wild]

On 12/02/2010 11:54 AM, luxInteg wrote:
> On Thursday 02 December 2010 07:48:55 Michael Wild wrote:
>> On 12/02/2010 08:25 AM, Alan W. Irwin wrote:
>>> On 2010-12-02 06:32+0100 Michael Wild wrote:
>>>> On 12/02/2010 12:37 AM, luxInteg wrote:
>>>>> On Tuesday 30 November 2010 22:43:34 luxInteg wrote:
>>>>>> Greetings
>>>>>>
>>>>>> I an learnig cmake.
>>>>>
>>>>> My test project is as follows:-
>>>>> linux machine with pyQt4, sip-4.10.2,qt-4.6.2 and cmake-2.8.2
>>>>>
>>>>> ---stepA: I have a file -fileA.sip.
>>>>> ---stepB: Upon execution of fileA.sip  two files  files -fileC.cpp and
>>>>> fileD.cpp    result,
>>>>> ---stepC: fileC.cpp and fileD,cpp are compiled into  a shared library.
>>>>>
>>>>> I am ok with stepC.  I do not know how to carry out step B
>>>>> execution  within
>>>>> cmake.
>>>>>
>>>>> advice would be appreciated.
>>>>>
>>>>> sincerely
>>>>> luxInteg
>>>>
>>>> Use ADD_CUSTOM_COMMAND.
>>>
>>> @Michael: that advice is not correct.  add_custom_command sets up a
>>> command to be run at "make" time. Instead, the execute_process command
>>> should be used to run a command at "CMake" time which is what the OP
>>> needs to generate his *.cpp files.
>>>
>>> @LuxInteg:  See the CMakeLists.txt file at
>>> http://plplot.svn.sourceforge.net/viewvc/plplot/trunk/bindings/qt_gui/pyq
>>> t4/
>>>
>>> for an example of generating source code with sip.
>>>
>>> Alan
>>
>> Huh, why can't he run sip at build time? If you do:
>>
>> find_program(SIP_EXECUTABLE sip)
>>
>> add_custom_command(OUTPUT
>>     ${CMAKE_CURRENT_BINARY_DIR}/fileC.cpp
>>     ${CMAKE_CURRENT_BINARY_DIR}/fileD.cpp
>>   COMMAND ${SIP_EXECUTABLE} -c ${CMAKE_CURRENT_BINARY_DIR}
>>     ${CMAKE_CURRENT_SOURCE_DIR}/fileA.sip
>>   DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/fileA.sip
>>   COMMENT "Processing ${CMAKE_CURRENT_SOURCE_DIR}/fileA.sip"
>>   VERBATIM)
>>
> thaks to you all for suggestions.
> 
> Before I saw the posts,  I had actually  'blind-man-fumbled' into something   
> that looks like this:-
> ---------------------
> set(sip_generator ../wherever/FileA.sip )
> set(generatorCMD "sip -C . ../wherever/FileA.sip" )
> 
> set(sipED-SRS
> ../path/to/fileC.cpp
> ../path/to/FileD.cpp
> )
> 
> 
> ADD_CUSTOM_COMMAND(
>    OUTPUT ${CMAKE_SOURCE_DIR}/${sipED-SRS}
>    COMMAND ${generatorCMD}
>    DEPENDS ${sip_generator} )
> ----------------------
> 
> (beforehand I would have to  actually designate some directory  in the  
> source-tree equivalent to '/path/to/'.  (And this I am unsure of.)
> 
> I have posted it   only because I want to know if I can group the generated 
> source files as  ${sipED_SRS} AND if so  how   the line  with  OUTPUT is set 
> to find them.
> 
> thanks again

No, you can't. CMake simply concatenates the strings when you do
${CMAKE_SOURCE_DIR}/${sipED-SRS}. You'll have to put CMAKE_BINARY_DIR
(or equivalent, like CMAKE_CURRENT_BINARY_DIR) in front of every element
in sipED-SRCS. A few additional issues:

- never EVER create output in the source tree, only in the build tree.
This is an absolute taboo and is verboten.

- it is a bad idea to use the hyphen (-) in a variable name. Replace it
by an underscore (_).

- don't use "sip" directly in your COMMAND, use FIND_EXECUTABLE first
like I showed in my example. This way the user of your project can
override the sip executable that is being used by specifying SIP_EXECUTABLE.

- use better variable names. "sip_generator" sounds like it refers to a
program. Better use "SIP_SOURCES" or similar. Also, sipED-SRS is pretty
bad, make it SIP_OUTPUT. People reading the code (even yourself in a
half-years time) will be very thankful to you...

Michael