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aa9220d3a0
Introduce a new signature for try_compile (and try_run) which removes the `bindir` argument and requires the SOURCES tag. This will eventually allow us to add other ways of providing sources, but also allows us to change the behavior without breaking compatibility. The old signature uses a special, but non-unique temporary location inside the specified `bindir`, which conventionally is just the project's build directory. The new signature unconditionally uses the a unique temporary directory which is unconditionally within the project's build directory (which is no longer separately specified). This ensures that successive runs do not overwrite previous runs, will simplify debugging, and should also, eventually, allow us to execute multiple trials in parallel.
142 lines
5.1 KiB
ReStructuredText
142 lines
5.1 KiB
ReStructuredText
try_run
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-------
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.. only:: html
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.. contents::
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Try compiling and then running some code.
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Try Compiling and Running Source Files
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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.. code-block:: cmake
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try_run(<runResultVar> <compileResultVar> SOURCES <srcfile...>
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[CMAKE_FLAGS <flags>...]
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[COMPILE_DEFINITIONS <defs>...]
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[LINK_OPTIONS <options>...]
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[LINK_LIBRARIES <libs>...]
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[COMPILE_OUTPUT_VARIABLE <var>]
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[COPY_FILE <fileName> [COPY_FILE_ERROR <var>]]
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[<LANG>_STANDARD <std>]
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[<LANG>_STANDARD_REQUIRED <bool>]
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[<LANG>_EXTENSIONS <bool>]
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[RUN_OUTPUT_VARIABLE <var>]
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[RUN_OUTPUT_STDOUT_VARIABLE <var>]
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[RUN_OUTPUT_STDERR_VARIABLE <var>]
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[OUTPUT_VARIABLE <var>]
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[WORKING_DIRECTORY <var>]
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[ARGS <args>...]
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)
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.. versionadded:: 3.25
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Try compiling a ``<srcfile>``. Returns ``TRUE`` or ``FALSE`` for success
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or failure in ``<compileResultVar>``. If the compile succeeded, runs the
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executable and returns its exit code in ``<runResultVar>``. If the
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executable was built, but failed to run, then ``<runResultVar>`` will be
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set to ``FAILED_TO_RUN``. See the :command:`try_compile` command for
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documentation of options common to both commands, and for information on how
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the test project is constructed to build the source file.
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This command also supports an alternate signature
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which was present in older versions of CMake:
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.. code-block:: cmake
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try_run(<runResultVar> <compileResultVar>
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<bindir> <srcfile|SOURCES srcfile...>
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[CMAKE_FLAGS <flags>...]
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[COMPILE_DEFINITIONS <defs>...]
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[LINK_OPTIONS <options>...]
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[LINK_LIBRARIES <libs>...]
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[COMPILE_OUTPUT_VARIABLE <var>]
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[COPY_FILE <fileName> [COPY_FILE_ERROR <var>]]
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[<LANG>_STANDARD <std>]
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[<LANG>_STANDARD_REQUIRED <bool>]
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[<LANG>_EXTENSIONS <bool>]
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[RUN_OUTPUT_VARIABLE <var>]
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[RUN_OUTPUT_STDOUT_VARIABLE <var>]
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[RUN_OUTPUT_STDERR_VARIABLE <var>]
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[OUTPUT_VARIABLE <var>]
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[WORKING_DIRECTORY <var>]
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[ARGS <args>...]
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)
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The options specific to ``try_run`` are:
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``COMPILE_OUTPUT_VARIABLE <var>``
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Report the compile step build output in a given variable.
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``OUTPUT_VARIABLE <var>``
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Report the compile build output and the output from running the executable
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in the given variable. This option exists for legacy reasons and is only
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supported by the old ``try_run`` signature.
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Prefer ``COMPILE_OUTPUT_VARIABLE`` and ``RUN_OUTPUT_VARIABLE`` instead.
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``RUN_OUTPUT_VARIABLE <var>``
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Report the output from running the executable in a given variable.
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``RUN_OUTPUT_STDOUT_VARIABLE <var>``
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.. versionadded:: 3.25
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Report the output of stdout from running the executable in a given variable.
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``RUN_OUTPUT_STDERR_VARIABLE <var>``
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.. versionadded:: 3.25
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Report the output of stderr from running the executable in a given variable.
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``WORKING_DIRECTORY <var>``
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.. versionadded:: 3.20
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Run the executable in the given directory. If no ``WORKING_DIRECTORY`` is
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specified, the executable will run in ``<bindir>`` or the current build
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directory.
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``ARGS <args>...``
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Additional arguments to pass to the executable when running it.
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Other Behavior Settings
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^^^^^^^^^^^^^^^^^^^^^^^
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Set the :variable:`CMAKE_TRY_COMPILE_CONFIGURATION` variable to choose
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a build configuration.
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Behavior when Cross Compiling
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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.. versionadded:: 3.3
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Use ``CMAKE_CROSSCOMPILING_EMULATOR`` when running cross-compiled
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binaries.
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When cross compiling, the executable compiled in the first step
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usually cannot be run on the build host. The ``try_run`` command checks
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the :variable:`CMAKE_CROSSCOMPILING` variable to detect whether CMake is in
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cross-compiling mode. If that is the case, it will still try to compile
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the executable, but it will not try to run the executable unless the
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:variable:`CMAKE_CROSSCOMPILING_EMULATOR` variable is set. Instead it
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will create cache variables which must be filled by the user or by
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presetting them in some CMake script file to the values the executable
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would have produced if it had been run on its actual target platform.
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These cache entries are:
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``<runResultVar>``
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Exit code if the executable were to be run on the target platform.
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``<runResultVar>__TRYRUN_OUTPUT``
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Output from stdout and stderr if the executable were to be run on
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the target platform. This is created only if the
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``RUN_OUTPUT_VARIABLE`` or ``OUTPUT_VARIABLE`` option was used.
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In order to make cross compiling your project easier, use ``try_run``
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only if really required. If you use ``try_run``, use the
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``RUN_OUTPUT_STDOUT_VARIABLE``, ``RUN_OUTPUT_STDERR_VARIABLE``,
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``RUN_OUTPUT_VARIABLE`` or ``OUTPUT_VARIABLE`` options only if really
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required. Using them will require that when cross-compiling, the cache
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variables will have to be set manually to the output of the executable.
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You can also "guard" the calls to ``try_run`` with an :command:`if`
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block checking the :variable:`CMAKE_CROSSCOMPILING` variable and
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provide an easy-to-preset alternative for this case.
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