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 set to
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=VALUE to be passed to the
cmake command-line used to drive the test build. The example in try_compile shows how values for variables
LINK_LIBRARIES are used.
-Ddefinition arguments to pass to
add_definitions in 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 <Imported Targets> from the calling project.
If this option is specified, any
-DLINK_LIBRARIES=... value given to the
CMAKE_FLAGS option 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.
Set the 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 the 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_VARIABLE option was used.
In order to make cross compiling your project easier, use
try_run 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 if block checking the CMAKE_CROSSCOMPILING variable and provide an easy-to-preset alternative for this case.