I was just replying to an acquaintance who was e-mailing me about CMake configuration when I realized that CMake configuration options which are only available depending on how other configuration options are set could be analyzed/displayed using graph theory (from a 5-minute study of graph theory from reading the first paragraph of the Wikipedia article on that :-) ).
I looked for a graphviz output file option for this in the cmake documentation and only found the --graphviz option which will "Generate a graphviz input file that will contain all the library and executable dependencies in the project." I used that for PLplot once. It worked and gave a pretty impressive visual demonstration of all the complicated and numerous PLplot dependencies. I wasn't surprised by any of those detailed relationships because I have them pretty much memorized, but such information would be a definite help to someone just getting up to speed with the PLplot build system (or any CMake-based build system) Could something similar be done for the dependencies between CMake options? I think that would be quite useful (especially if it included the documentation of the options) for further graphviz analysis and display of the relationships between the totality of all the CMake options for a given build system. The problem with using cmake-gui for this task (or the equivalent cmake + looking at the resulting CMakeCache.txt file) is you only see the first layer of possible configurations as opposed to the totality of options you could visualize with a graphviz file. Moving to a related topic, if you run cmake with no -D options in an empty build tree, you get the first layer of options available to you for a particular build system in nicely documented form in CMakeCache.txt. Once you set some of those as cmake -D options (always run within an empty build tree), then you get the next layer of options available to you, and so on, with each iteration accumulating the command-line -D options you need from the combination of previous sets of options and the new ones. I am not familiar with the CMake GUI's, cmake-gui and ccmake, but I assume they do exactly this same task of displaying the documented currently available options that can be set depending on the previous "layer" of set options. But do any of these GUI's have an undo button (and redo button to undo the undo) so you can easily and consistently navigate to any previous layer of options that you have effectively tried before for an empty build tree like you can so easily do (simply using up arrow or down arrow to remove the build tree and navigate to some other previously tried set of -D options) with the command-line approach? It appears from discussions with my GUI-oriented acquaintance, undo and redo buttons would be worthwhile now if those haven't been implemented yet in the CMake GUI's. I hope in this post I have given this audience some useful food for thought about potential improvements to CMake concerning (1) a graphviz output file of all options including their documentation to help display an overview of all options and their logical relationships and (2) possibly additional ease of use for CMake GUI's with undo and redo (if those haven't been implemented yet) in setting various layers of those options that become available depending on other options set in previous layers. I admit to being unfamiliar with the CMake GUI's (because I was not impressed with them years ago), but if they already have undo and redo implemented perhaps it is time to learn about them (and especially if they are exactly equivalent to the situation I understand which is running cmake in an empty build tree with various layers of possible -D options set on the cmake command line). Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ _______________________________________________ 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
