[CMake] Execute CMake process not working: source directory confusion

[Michael Powell]

On Thu, Sep 28, 2017 at 1:42 PM, Petr Kmoch <petr.kmoch at gmail.com> wrote:
> (Added list back to copy)
>
> On 28 September 2017 at 18:53, Michael Powell <mwpowellhtx at gmail.com> wrote:
>>
>> [...]
>> >>
>> >> Curious CMake would "see" the ENTIRE argument string as
>> >> "path-to-source" though. Not sure quite what's going on with that,
>> >> though.
>> >
>> >
>> > That's because you're constructing CPPNNG_NNG_CMAKE_OPTIONS as a single
>> > string containing spaces. Spaces *in strings* do not delimit CMake
>> > arguments, even if spaces in CMake file syntax do. In other words:
>> >
>> >  foo(a b c)
>> >
>> > calls 'foo' with 3 arguments: "a", "b", and "c".
>> >
>> >  set(args a b c)
>> >  foo(${args})
>> >
>> > also calls 'foo' with these 3 arguments.
>> >
>> > However,
>> >
>> >   set(args "a b c")
>> >   foo(${args})
>> >
>> > calls 'foo' with only ONE argument: the string "a b c".
>> >
>> > You need to drop one level of quoting inside your cppnng_nng_add_*
>> > macros.
>> >
>> [...]
>>
>> Thanks for that insight!
>>
>> I ended up with something like this:
>>
>> message (STATUS "Invoking CMake: \"${CMAKE_COMMAND}\"
>> ${CPPNNG_NNG_CMAKE_OPTIONS} \"${GIT_SUBMODULE_NNG_REPO_DIR}\"")
>>
>> execute_process (
>>     COMMAND "\"${CMAKE_COMMAND}\" ${CPPNNG_NNG_CMAKE_OPTIONS}
>> \"${GIT_SUBMODULE_NNG_REPO_DIR}\""
>>     WORKING_DIRECTORY "${GIT_SUBMODULE_NNG_REPO_DIR}"
>>     RESULT_VARIABLE CPPNN_NNG_CONFIG_EC
>>     OUTPUT_VARIABLE CPPNN_NNG_CONFIG_MSG
>> )
>>
>> But which is now yielding an output message " (Access is denied)" (no EC).
>>
>> Console output:
>>
>> Invoking CMake: "C:/Dev/CMake/bin/cmake.exe" -G "Visual Studio 14 2015
>> Win64" --build "G:/Source/Spikes/nanomsg/cppnngswig-testing/build/nng"
>> -D
>> CMAKE_CONFIGURATION_TYPES:STRING="Debug\;Release\;MinSizeRel\;RelWithDebInfo"
>> -D
>> CMAKE_INSTALL_PREFIX:STRING="G:/Source/Spikes/nanomsg/cppnngswig-testing/build/nng"
>> -D NNG_ENABLE_COVERAGE:BOOL=OFF -D NNG_ENABLE_DOC:BOOL=OFF -D
>> NNG_ENABLE_NNGCAT:BOOL=OFF -D NNG_ENABLE_TESTS:BOOL=OFF -D
>> NNG_ENABLE_TOOLS:BOOL=OFF -D NNG_ENABLE_ZEROTIER:BOOL=OFF
>> "G:/Source/Spikes/nanomsg/cppnngswig-testing/repos/nng"
>
>
> You're still putting quotes where there shouldn't be any. Look at this:
>
>    COMMAND "\"${CMAKE_COMMAND}\" ${CPPNNG_NNG_CMAKE_OPTIONS}
> \"${GIT_SUBMODULE_NNG_REPO_DIR}\""
>
> Since the entire argument to COMMAND is in quotes, it's interpreted as the
> *name* of the command you want to execute. What you want is to pass multiple
> arguments to execute_process: one for the binary, and one for each
> command-line argument to it. CMake will take care of proper escpaing for
> you. So your code should look like this:

Ah ok... I see it now. And the result is much MUCH better. Thanks!

> execute_process (
>     COMMAND "${CMAKE_COMMAND}" ${CPPNNG_NNG_CMAKE_OPTIONS}
> "${GIT_SUBMODULE_NNG_REPO_DIR}"
>     WORKING_DIRECTORY "${GIT_SUBMODULE_NNG_REPO_DIR}"
>     RESULT_VARIABLE CPPNN_NNG_CONFIG_EC
>     OUTPUT_VARIABLE CPPNN_NNG_CONFIG_MSG
> )
>
> In fact, you can even drop the quotes around the variable dereferncing if
> you want to; they're only necessary if the arguments can contain a
> semi-colon (as that would split them into multiple CMake arguments). But
> they're safe to keep.
>
> Petr
>