[CMake] How to handle options with more than two possible values?

[YuGiOhJCJ Mailing-List]

Thanks it works perfectly!

On Thu, 13 Oct 2016 13:41:00 +0200
Petr Kmoch <petr.kmoch at gmail.com> wrote:

> Hi.
> 
> option() is a handy shortcut for boolean options, but it's little more than
> syntactic sugar for a cache variable of type BOOL. To create a tristate
> variable, you can do this:
> 
>   set(ENABLE_SOMETHING AUTO CACHE STRING "Enable SOMETHING support")  #
> create the variable
>   set_property(CACHE ENABLE_SOMETHING PROPERTY STRINGS AUTO ON OFF)  #
> define list of values GUI will offer for the variable
> 
> Then, you can test the variable like this:
> 
>   if(ENABLE_SOMETHING STREQUAL "AUTO")
>     # AUTO was used
>   elseif(ENABLE_SOMETHING)
>     # a true value (such as ON) was used
>   else()
>     # a false value (such as OFF) was used
>   endif()
> 
> Hope this helps.
> 
> Petr
> 
> On 13 October 2016 at 13:32, YuGiOhJCJ Mailing-List via CMake <
> cmake at cmake.org> wrote:
> 
> > Hello,
> >
> > Regarding the cmake-commands manual [1], the "option" command seems to
> > take as argument a boolean constant that can have the two possible values:
> > ON or OFF.
> >
> > I would like to use three possible values for an option: AUTO (as default
> > value), ON or OFF.
> >
> > Example:
> > option(ENABLE_SOMETHING "Enable SOMETHING support" AUTO)
> >
> > But of course this example is wrong because "AUTO" is not ON or OFF.
> >
> > Regarding the cmake-commands manual [2], the "if" command seems to return
> > TRUE when the boolean constant is 1, ON, YES, TRUE, Y, or a non-zero number.
> > It returns FALSE when the boolean constant is 0, OFF, NO, FALSE, N,
> > IGNORE, NOTFOUND, the empty string, or ends in the suffix -NOTFOUND.
> >
> > I would like to check the value myself.
> >
> > Example:
> > if(ENABLE_SOMETHING=AUTO)
> >         message(STATUS "ENABLE_SOMETHING=AUTO")
> > endif()
> > if(ENABLE_SOMETHING=ON)
> >         message(STATUS "ENABLE_SOMETHING=ON")
> > endif()
> > if(ENABLE_SOMETHING=OFF)
> >         message(STATUS "ENABLE_SOMETHING=OFF")
> > endif()
> >
> > But of course this example is wrong because "=" is not accepted for an
> > expression in a "if" command.
> >
> > So my question is: How to handle options with more than two possible
> > values?
> >
> > Thank you.
> > Best regards.
> >
> > [1] https://cmake.org/cmake/help/v3.7/command/option.html
> > [2] https://cmake.org/cmake/help/v3.7/command/if.html
> > --
> >
> > 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:
> > http://public.kitware.com/mailman/listinfo/cmake
> >