You can add PARENT_SCOPE to set command to set the value on the calling code.
Regards, Dvir From: CMake [mailto:[email protected]] On Behalf Of J Decker Sent: Tuesday, January 30, 2018 18:07 To: Petr Kmoch <[email protected]> Cc: CMake Mail List <[email protected]> Subject: [Digital Signature Failure] Re: [CMake] Hard to do if in Macro Okay... but then with function I can't set external variables; but if( __ANDROID__ ) works. `result` never changes. --------------------------- set( __ANDROID__ 1 ) function( test __ANDROID__ RETVAL ) if( ${__ANDROID__} EQUAL 1 OR ${__ANDROID__} STREQUAL "ON") set( ${RETVAL} ${${RETVAL}} qwer2 ) message( "Included..... " ) endif( ${__ANDROID__} EQUAL 1 OR ${__ANDROID__} STREQUAL "ON") if( __ANDROID__ ) set( ${RETVAL} ${${RETVAL}} asdf ) message( "ALWAYS Included ${__ANDROID__}" ) endif( __ANDROID__ ) endfunction( test ) set( result "default" ) test( __ANDROID__ "result" ) message( "REsult:${result}" ) test( ${__ANDROID__} "result" ) message( "REsult:${result}" ) test( OFF "result") message( "REsult:${result}" ) --------------------------- On Tue, Jan 30, 2018 at 12:35 AM, Petr Kmoch <[email protected]<mailto:[email protected]>> wrote: Macros aren't functions, and macro parameters aren't CMake variables. Expanding a macro parameter is effectively *textual* substitution, whereas dereferencing a CMake variable is a semantic one. In other words, inside your macro, the text __ANDROID__ (when not expanded) never refers to the macro parameter. Macro parameters "don't exist" outside of expansion context. The `if(__ANDROID__)` bit therefore always refers to the variable __ANDROID__, never to the macro parameter __ANDROID__. You still don't have to spell out the conditional as explicitly as you're doing it now, but you have to expand the parameter: macro(test __ANDROID__) if(${__ANDROID__}) message( "Included..... " ) endif() endmacro() This is what the evaluation will look like based on how you call it: test(__ANDROID__) -> if(__ANDROID__) -> refers to the variable set(__ANDROID__ 1) test(${__ANDROID__}) -> if(1) set(__ANDROID__ 0) test(${__ANDROID__}) -> if(0) test(OFF) -> if(OFF) CMake macros have a lot of specific and potentially weird/counterintuitive behaviour. In general, you should always write your commands as functions and only resort to macros if you explicitly need their specific behaviour. Petr On 30 January 2018 at 09:11, J Decker <[email protected]<mailto:[email protected]>> wrote: Why do I have to do if( ${M__ANDROID__} EQUAL 1 OR ${M__ANDROID__} STREQUAL "ON") endif( ${M__ANDROID__} EQUAL 1 OR ${M__ANDROID__} STREQUAL "ON") in a macro like... ---------------------- set( __ANDROID__ 1 ) macro( test __ANDROID__ ) if( ${__ANDROID__} EQUAL 1 OR ${__ANDROID__} STREQUAL "ON") message( "Included..... " ) endif( ${__ANDROID__} EQUAL 1 OR ${__ANDROID__} STREQUAL "ON") if( __ANDROID__ ) message( "ALWAYS Included ${__ANDROID__}" ) endif( __ANDROID__ ) endmacro( test ) test( __ANDROID__ ) test( ${__ANDROID__} ) test( OFF ) ---------- Output Included..... ALWAYS Included __ANDROID__ Included..... ALWAYS Included 1 ALWAYS Included OFF -- Powered by www.kitware.com<http://www.kitware.com> Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: https://cmake.org/mailman/listinfo/cmake
-- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: https://cmake.org/mailman/listinfo/cmake
