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| -rw-r--r-- | Help/manual/cmake-generator-expressions.7.rst | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Help/manual/cmake-generator-expressions.7.rst b/Help/manual/cmake-generator-expressions.7.rst index eb9c9fe..b5c4457 100644 --- a/Help/manual/cmake-generator-expressions.7.rst +++ b/Help/manual/cmake-generator-expressions.7.rst @@ -440,3 +440,25 @@ Output-Related Expressions Content of ``...`` converted to shell path style. For example, slashes are converted to backslashes in Windows shells and drive letters are converted to posix paths in MSYS shells. The ``...`` must be an absolute path. + +Debugging +========= + +Since generator expressions are evaluated during generation of the buildsystem, +and not during processing of ``CMakeLists.txt`` files, it is not possible to +inspect their result with the :command:`message()` command. + +One possible way to generate debug messages is to add a custom target, + +.. code-block:: cmake + + add_custom_target(genexdebug COMMAND ${CMAKE_COMMAND} -E echo "$<...>") + +The shell command ``make genexdebug`` (invoked after execution of ``cmake``) +would then print the result of ``$<...>``. + +Another way is to write debug messages to a file: + +.. code-block:: cmake + + file(GENERATE OUTPUT filename CONTENT "$<...>") |