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Diffstat (limited to 'Help/manual/cmake-generator-expressions.7.rst')
| -rw-r--r-- | Help/manual/cmake-generator-expressions.7.rst | 54 |
1 files changed, 49 insertions, 5 deletions
diff --git a/Help/manual/cmake-generator-expressions.7.rst b/Help/manual/cmake-generator-expressions.7.rst index c47a7c4..189c3ef 100644 --- a/Help/manual/cmake-generator-expressions.7.rst +++ b/Help/manual/cmake-generator-expressions.7.rst @@ -40,10 +40,6 @@ otherwise expands to nothing. Available logical expressions are: -``$<0:...>`` - Empty string (ignores ``...``) -``$<1:...>`` - Content of ``...`` ``$<BOOL:...>`` ``1`` if the ``...`` is true, else ``0`` ``$<AND:?[,?]...>`` @@ -92,7 +88,47 @@ Available logical expressions are: increases the required :prop_tgt:`C_STANDARD` or :prop_tgt:`CXX_STANDARD` for the 'head' target, an error is reported. See the :manual:`cmake-compile-features(7)` manual for information on - compile features. + compile features and a list of supported compilers. +``$<COMPILE_LANGUAGE:lang>`` + ``1`` when the language used for compilation unit matches ``lang``, + otherwise ``0``. This expression used to specify compile options for + source files of a particular language in a target. For example, to specify + the use of the ``-fno-exceptions`` compile option (compiler id checks + elided): + + .. code-block:: cmake + + add_executable(myapp main.cpp foo.c bar.cpp) + target_compile_options(myapp + PRIVATE $<$<COMPILE_LANGUAGE:CXX>:-fno-exceptions> + ) + + This generator expression has limited use because it is not possible to + use it with the Visual Studio generators. Portable buildsystems would + not use this expression, and would create separate libraries for each + source file language instead: + + .. code-block:: cmake + + add_library(myapp_c foo.c) + add_library(myapp_cxx foo.c) + target_compile_options(myapp_cxx PUBLIC -fno-exceptions) + add_executable(myapp main.cpp) + target_link_libraries(myapp myapp_c myapp_cxx) + + The ``Makefile`` and ``Ninja`` based generators can also use this + expression to specify compile-language specific compile definitions + and include directories: + + .. code-block:: cmake + + add_executable(myapp main.cpp foo.c bar.cpp) + target_compile_definitions(myapp + PRIVATE $<$<COMPILE_LANGUAGE:CXX>:COMPILING_CXX> + ) + target_include_directories(myapp + PRIVATE $<$<COMPILE_LANGUAGE:CXX>:/opt/foo/cxx_headers> + ) Informational Expressions ========================= @@ -174,6 +210,10 @@ Available informational expressions are: ``$<INSTALL_PREFIX>`` Content of the install prefix when the target is exported via :command:`install(EXPORT)` and empty otherwise. +``$<COMPILE_LANGUAGE>`` + The compile language of source files when evaluating compile options. See + the unary version for notes about portability of this generator + expression. Output Expressions ================== @@ -197,6 +237,10 @@ where ``${prop}`` refers to a helper variable:: Available output expressions are: +``$<0:...>`` + Empty string (ignores ``...``) +``$<1:...>`` + Content of ``...`` ``$<JOIN:list,...>`` Joins the list with the content of ``...`` ``$<ANGLE-R>`` |