try_run¶
Try compiling and then running some code.
Try Compiling and Running Source Files¶
try_run(<runResultVar> <compileResultVar>
[SOURCES_TYPE <type>]
<SOURCES <srcfile...> |
SOURCE_FROM_CONTENT <name> <content> |
SOURCE_FROM_VAR <name> <var> |
SOURCE_FROM_FILE <name> <path> >...
[LOG_DESCRIPTION <text>]
[NO_CACHE]
[NO_LOG]
[CMAKE_FLAGS <flags>...]
[COMPILE_DEFINITIONS <defs>...]
[LINK_OPTIONS <options>...]
[LINK_LIBRARIES <libs>...]
[COMPILE_OUTPUT_VARIABLE <var>]
[COPY_FILE <fileName> [COPY_FILE_ERROR <var>]]
[<LANG>_STANDARD <std>]
[<LANG>_STANDARD_REQUIRED <bool>]
[<LANG>_EXTENSIONS <bool>]
[RUN_OUTPUT_VARIABLE <var>]
[RUN_OUTPUT_STDOUT_VARIABLE <var>]
[RUN_OUTPUT_STDERR_VARIABLE <var>]
[WORKING_DIRECTORY <var>]
[ARGS <args>...]
)
New in version 3.25.
Try building an executable from one or more source files. Build success
returns TRUE
and build failure returns FALSE
in <compileResultVar>
.
If the build succeeds, this runs the executable and stores the exit code in
<runResultVar>
. If the executable was built, but failed to run, then
<runResultVar>
will be set to FAILED_TO_RUN
. See command
try_compile()
for documentation of options common to both commands,
and for information on how the test project is constructed to build the source
file.
One or more source files must be provided. Additionally, one of SOURCES
and/or SOURCE_FROM_*
must precede other keywords.
New in version 3.26: This command records a
configure-log try_run event
if the NO_LOG
option is not specified.
This command supports an alternate signature for CMake older than 3.25. The signature above is recommended for clarity.
try_run(<runResultVar> <compileResultVar>
<bindir> <srcfile|SOURCES srcfile...>
[CMAKE_FLAGS <flags>...]
[COMPILE_DEFINITIONS <defs>...]
[LINK_OPTIONS <options>...]
[LINK_LIBRARIES <libs>...]
[LINKER_LANGUAGE <lang>]
[COMPILE_OUTPUT_VARIABLE <var>]
[COPY_FILE <fileName> [COPY_FILE_ERROR <var>]]
[<LANG>_STANDARD <std>]
[<LANG>_STANDARD_REQUIRED <bool>]
[<LANG>_EXTENSIONS <bool>]
[RUN_OUTPUT_VARIABLE <var>]
[OUTPUT_VARIABLE <var>]
[WORKING_DIRECTORY <var>]
[ARGS <args>...]
)
Options¶
The options specific to try_run
are:
COMPILE_OUTPUT_VARIABLE <var>
Report the compile step build output in a given variable.
OUTPUT_VARIABLE <var>
Report the compile build output and the output from running the executable in the given variable. This option exists for legacy reasons and is only supported by the old
try_run
signature. PreferCOMPILE_OUTPUT_VARIABLE
andRUN_OUTPUT_VARIABLE
instead.RUN_OUTPUT_VARIABLE <var>
Report the output from running the executable in a given variable.
RUN_OUTPUT_STDOUT_VARIABLE <var>
New in version 3.25.
Report the output of stdout from running the executable in a given variable.
RUN_OUTPUT_STDERR_VARIABLE <var>
New in version 3.25.
Report the output of stderr from running the executable in a given variable.
WORKING_DIRECTORY <var>
New in version 3.20.
Run the executable in the given directory. If no
WORKING_DIRECTORY
is specified, the executable will run in<bindir>
or the current build directory.ARGS <args>...
Additional arguments to pass to the executable when running it.
Other Behavior Settings¶
Set variable CMAKE_TRY_COMPILE_CONFIGURATION
to choose a build
configuration:
For multi-config generators, this selects which configuration to build.
For single-config generators, this sets
CMAKE_BUILD_TYPE
in the test project.
Behavior when Cross Compiling¶
New in version 3.3: Use CMAKE_CROSSCOMPILING_EMULATOR
when running cross-compiled binaries.
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:
<runResultVar>
Exit code if the executable were to be run on the target platform.
<runResultVar>__TRYRUN_OUTPUT
Output from stdout and stderr if the executable were to be run on the target platform. This is created only if the
RUN_OUTPUT_VARIABLE
orOUTPUT_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
RUN_OUTPUT_STDOUT_VARIABLE
, RUN_OUTPUT_STDERR_VARIABLE
,
RUN_OUTPUT_VARIABLE
or 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.