try_compile
: Try building some code.try_compile(RESULT_VAR <bindir> <srcdir>
<projectName> [targetName] [CMAKE_FLAGS flags...]
[OUTPUT_VARIABLE <var>])
Try building a project. In this form, srcdir should contain a complete CMake project with a CMakeLists.txt file and all sources. The bindir and srcdir will not be deleted after this command is run. Specify targetName to build a specific target instead of the 'all' or 'ALL_BUILD' target.
try_compile(RESULT_VAR <bindir> <srcfile>
[CMAKE_FLAGS flags...]
[COMPILE_DEFINITIONS flags...]
[OUTPUT_VARIABLE <var>]
[COPY_FILE <fileName>])
Try building a source file into an executable. In this form the user need only supply a source file that defines a 'main'. CMake will create a CMakeLists.txt file to build the source as an executable. Specify COPY_FILE to get a copy of the linked executable at the given fileName.
In this version all files in bindir/CMakeFiles/CMakeTmp will be cleaned automatically. For debugging, --debug-trycompile can be passed to cmake to avoid this clean. However, multiple sequential try_compile operations reuse this single output directory. If you use --debug-trycompile, you can only debug one try_compile call at a time. The recommended procedure is to configure with cmake all the way through once, then delete the cache entry associated with the try_compile call of interest, and then re-run cmake again with --debug-trycompile.
Some extra flags that can be included are, INCLUDE_DIRECTORIES, LINK_DIRECTORIES, and LINK_LIBRARIES. COMPILE_DEFINITIONS are -Ddefinition that will be passed to the compile line. try_compile creates a CMakeList.txt file on the fly that looks like this:
add_definitions( <expanded COMPILE_DEFINITIONS from calling cmake>)
include_directories(${INCLUDE_DIRECTORIES})
link_directories(${LINK_DIRECTORIES})
add_executable(cmTryCompileExec sources)
target_link_libraries(cmTryCompileExec ${LINK_LIBRARIES})
In both versions of the command, if OUTPUT_VARIABLE is specified, then the output from the build process is stored in the given variable. The success or failure of the try_compile, i.e. TRUE or FALSE respectively, is returned in RESULT_VAR. CMAKE_FLAGS can be used to pass -DVAR:TYPE=VALUE flags to the cmake that is run during the build. Set variable CMAKE_TRY_COMPILE_CONFIGURATION to choose a build configuration.