Try compiling and then running some code.
try_run(RUN_RESULT_VAR COMPILE_RESULT_VAR bindir srcfile [CMAKE_FLAGS <flags>...] [COMPILE_DEFINITIONS <defs>...] [LINK_LIBRARIES <libs>...] [COMPILE_OUTPUT_VARIABLE <var>] [RUN_OUTPUT_VARIABLE <var>] [OUTPUT_VARIABLE <var>] [ARGS <args>...])
Try compiling a
FALSE for success
or failure in
COMPILE_RESULT_VAR. If the compile succeeded, runs the
executable and returns its exit code in
RUN_RESULT_VAR. If the
executable was built, but failed to run, then
RUN_RESULT_VAR will be
FAILED_TO_RUN. See the
try_compile() command for
information on how the test project is constructed to build the source file.
The options are:
- Specify flags of the form
-DVAR:TYPE=VALUEto be passed to the
cmakecommand-line used to drive the test build. The example in
try_compile()shows how values for variables
-Ddefinitionarguments to pass to
add_definitionsin the generated test project.
- Report the compile step build output in a given variable.
Specify libraries to be linked in the generated project. The list of libraries may refer to system libraries and to Imported Targets from the calling project.
If this option is specified, any
-DLINK_LIBRARIES=...value given to the
CMAKE_FLAGSoption will be ignored.
- Report the compile build output and the output from running the executable
in the given variable. This option exists for legacy reasons. Prefer
- Report the output from running the executable in a given variable.
CMAKE_TRY_COMPILE_CONFIGURATION variable to choose
a build configuration.
When cross compiling, the executable compiled in the first step
usually cannot be run on the build host. The
try_run command checks
CMAKE_CROSSCOMPILING variable to detect whether CMake is in
cross-compiling mode. If that is the case, it will still try to compile
the executable, but it will not try to run the executable unless the
CMAKE_CROSSCOMPILING_EMULATOR variable is set. Instead it
will create cache variables which must be filled by the user or by
presetting them in some CMake script file to the values the executable
would have produced if it had been run on its actual target platform.
These cache entries are:
- Exit code if the executable were to be run on the target platform.
- Output from stdout and stderr if the executable were to be run on
the target platform. This is created only if the
OUTPUT_VARIABLEoption was used.
In order to make cross compiling your project easier, use
only if really required. If you use
try_run, use the
OUTPUT_VARIABLE options only if really
required. Using them will require that when cross-compiling, the cache
variables will have to be set manually to the output of the executable.
You can also “guard” the calls to
try_run with an
block checking the
CMAKE_CROSSCOMPILING variable and
provide an easy-to-preset alternative for this case.