[cmake-developers] generator expression for path slash conversion (was: ExternalProject: Use native paths as substitute for directory tokens)

[CHEVRIER, Marc]

Sorry for the false assertion.
I assumed, wrongly, that add_custom_command had same behaviour as execute_process for which the doc clearly explains that System API are used (no shell used).
So, adding some precisions on how add_custom_command (and add_custom_target I presume) launch specified commands should be a nice enhancement.

Marc





On 28/08/15 15:59, "cmake-developers on behalf of Brad King" <cmake-developers-bounces at cmake.org on behalf of brad.king at kitware.com> wrote:

>On 08/28/2015 04:06 AM, CHEVRIER, Marc wrote:
>> Offering generator-expressions is a very good idea because it offers
>> a global solution to this problem.
>> 
>> Now regarding the name of the generator, may be TO_NATIVE_PATH is
>> not judicious, (even if problems explained in
>> http://www.cmake.org/Bug/view.php?id=5939 are, in my point of view,
>> linked to platforms not well handled rather than wrong semantic of
>> TO_NATIVE_PATH) but PATH_FOR_SHELL is, as well, ambiguous at least
>> for two reasons:
>> * commands defined in add_custom_command, for example, are directly
>>   executed without any shell evolved
>
>No, add_custom_command results in a generated build system rule for
>the specified command, and that always runs in a shell at build time.
>One can see the conversions done properly internally to CMake for
>generating references to source and object files on toolchain command
>lines, for example.
>
>> * A system can have multiple shells supporting different paths syntax.
>>   For example, on windows, my shell is tcsh which handle paths with '/'
>>   rather than '\'
>
>It would be defined as the shell in which the build system will run
>the commands.  We should choose a name accordingly.
>
>-Brad
>
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