On Wednesday, July 30, 2014 14:59:46 Ghyslain Leclerc wrote: > Hello, > > First post here. Sorry if its too long. Simply trying to be as clear as I > can be. > > I am trying to make sense of the various ways to set a variable and how one > can shadow the other. Long story short, I am trying to get the following > behaviour for a variable in a script: > > 1 - check if MYVAR exists > 1.1 - If it does, test its validity and set a second variable > named MYVAR_VALID to TRUE or FALSE > > 2 - if MYVAR does not exist or if MYVAR_VALID is FALSE, inspect system for > information and set MYVAR (with FORCE in the cache) and MYVAR_VALID (not in > cache, but does not seem to make a difference). > > Hope this is written clearly enough to be understood. Sorry, english is not > my first language. Anyhow, I get the following behaviour easily except in > one case, which is the reason for my question. These are the cases I have > tested : > > - Start with empty cache and call ccmake. Then, MYVAR does not exist. My > script inspects the system, sets the value, sets MYVAR_VALID to TRUE and > stops. On successive runs, the variable is defined and valid, so the > system is not inspected again. Everything is fine. > > - Start with empty cache. Run it once, but can’t find a valid entry (or > find a wrong one somehow, but that’s practically impossible since the code > in my script to inspect the system and to test the variable are basically > the same. I digress, sorry). Set MYVAR_VALID to FALSE. User can set the > value to a valid one and on next run, the script will set MYVAR_VALID to > TRUE and then, we are back to variable defined and valid. Everything is > fine. > > - Start with "non-empty cache" because ccmake (or cmake) is called with > -DMYVAR:PATH="/Users/“, for instance. If the value set on command line is > fine, then MYVAR_VALID will be set to TRUE on the first run and no system > inspection is necessary. The value is now set and valid. Everything is > fine. > > Now, for my problem : > - Start with "non-empty cache" because ccmake (or cmake) is called with > -DMYVAR:PATH="/Users/“, for instance. But this time, the value is not a > valid one. Then, the variable is defined but not valid. So on the first > run, the script will inspect the system. If it can find a valid value, I > would like my script to override the variable with the valid one. Then, set > to valid and so on and so forth... > > I have not been able to do this. I can find the correct value, I can set > the new value, but it is not used. I mean by that that I have inspected > the CMakeCache.txt file and when I call ccmake, the cache contains the > value set on the command line. Then, I launch my cmake script and output > the values of MYVAR and MYVAR_VALID and they are respectively the one of > the command line and FALSE. Then, I find the correct value for MYVAR and > try and set it. When I inspect the cache, it seems the value has > effectively been overwritten.
You are using set(... FORCE), right ? > But when I try to output the new variables, > it seems to remain stuck at the value provided on the command line. I have > tried using unset( MYVAR ) in scope, How do you mean that ? IIRC -DVAR=value sets the cache variable. Not sure, it seems -D maybe also sets the non-cache variable ? Then uset() should have worked. Can you post a small example to reproduce it ? Alex -- 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
