Hi Tyler, That's because I would like to use FOO as a sort of tribool variable. Besides TRUE and FALSE, I'd like to know whether FOO was defined at all. If not that qualifies and neither TRUE nor FALSE.
'IF(FOO)' will return FALSE, either when FOO is FALSE or when FOO is not DEFINED. Therefore, I wanted to resort to 'IF DEFINED(FOO)'. Best regards, Marcel. On Thu, 2010-07-01 at 07:43 -0700, Tyler Roscoe wrote: > Marcel, > > Maybe I missed it earlier ITT, but I don't understand why you can't just > use if(FOO) instead? > > tyler > > On Thu, Jul 01, 2010 at 11:53:33AM +0200, Marcel Loose wrote: > > Hi Fraser, > > > > It doesn't. Well, partly it does, but unfortunately setting FOO to an > > empty string doesn't make it undefined; i.e. if(DEFINED FOO) will be > > TRUE. I've decided to use 'if("${FOO}" MATCHES "^$")' instead. > > > > Best regards, > > Marcel Loose. > > > > On Wed, 2010-06-30 at 10:57 +0100, Fraser Hutchison wrote: > > > I think 'set(FOO "" CACHE INTERNAL "Foo")' should do the trick. > > > > > > All the best, > > > > > > Fraser. > > > > > > > > > > > > On 30/06/2010 9:38 AM, Marcel Loose wrote: > > > > Hi all, > > > > > > > > Is there a way to unset a cache variable, i.e. make it undefined, > > > > *without* using unset(). > > > > > > > > My reason for asking is that my CMake scripts need to be backward > > > > compatible with every 2.6 version. Unfortunately, unset() was added > > in a > > > > patch release (2.6.3 if I recall correctly), so I cannot use it. > > > > > > > > The problem is that, though 'set(FOO)' will make FOO undefined, this > > > > doesn't seem to work for 'set(FOO CACHE INTERNAL "Foo")'. > > > > > > > > Any ideas how to accomplish this? > > > > > > > > Best regards, > > > > Marcel Loose. > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > Powered by www.kitware.com > > > > > > > > Visit other Kitware open-source projects at > > http://www.kitware.com/opensource/opensource.html > > > > > > > > Please keep messages on-topic and check the CMake FAQ at: > > http://www.cmake.org/Wiki/CMake_FAQ > > > > > > > > Follow this link to subscribe/unsubscribe: > > > > http://www.cmake.org/mailman/listinfo/cmake > > > > > > > > > > _______________________________________________ > > Powered by www.kitware.com > > > > Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html > > > > Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ > > > > Follow this link to subscribe/unsubscribe: > > http://www.cmake.org/mailman/listinfo/cmake _______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake