53 lines
2.2 KiB
ReStructuredText
53 lines
2.2 KiB
ReStructuredText
try_run
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-------
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Try compiling and then running some code.
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::
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try_run(RUN_RESULT_VAR COMPILE_RESULT_VAR
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bindir srcfile [CMAKE_FLAGS <Flags>]
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[COMPILE_DEFINITIONS <flags>]
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[COMPILE_OUTPUT_VARIABLE comp]
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[RUN_OUTPUT_VARIABLE run]
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[OUTPUT_VARIABLE var]
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[ARGS <arg1> <arg2>...])
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Try compiling a srcfile. Return TRUE or FALSE for success or failure
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in COMPILE_RESULT_VAR. Then if the compile succeeded, run the
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executable and return its exit code in RUN_RESULT_VAR. If the
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executable was built, but failed to run, then RUN_RESULT_VAR will be
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set to FAILED_TO_RUN. COMPILE_OUTPUT_VARIABLE specifies the variable
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where the output from the compile step goes. RUN_OUTPUT_VARIABLE
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specifies the variable where the output from the running executable
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goes.
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For compatibility reasons OUTPUT_VARIABLE is still supported, which
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gives you the output from the compile and run step combined.
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Cross compiling issues
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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. try_run() checks the
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CMAKE_CROSSCOMPILING variable to detect whether CMake is in
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crosscompiling mode. If that's the case, it will still try to compile
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the executable, but it will not try to run the executable. 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 variables are RUN_RESULT_VAR (explanation see above) and if
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RUN_OUTPUT_VARIABLE (or OUTPUT_VARIABLE) was used, an additional cache
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variable RUN_RESULT_VAR__COMPILE_RESULT_VAR__TRYRUN_OUTPUT.This is
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intended to hold stdout and stderr from the executable.
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In order to make cross compiling your project easier, use try_run only
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if really required. If you use try_run, use RUN_OUTPUT_VARIABLE (or
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OUTPUT_VARIABLE) only if really required. Using them will require
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that when crosscompiling, the cache variables will have to be set
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manually to the output of the executable. You can also "guard" the
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calls to try_run with if(CMAKE_CROSSCOMPILING) and provide an
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easy-to-preset alternative for this case.
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Set variable CMAKE_TRY_COMPILE_CONFIGURATION to choose a build
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configuration.
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