Hi all, We'd like to use CMake instead of autotools to build native (C/C++) code in Hadoop. There are a lot of reasons to want to do this. For one thing, it is not feasible to use autotools on the Windows platform, because it depends on UNIX shell scripts, the m4 macro processor, and some other pieces of infrastructure which are not present on Windows.
For another thing, CMake builds are substantially simpler and faster, because there is only one layer of generated code. With autotools, you have automake generating m4 code which autoconf reads, which it uses to generate a UNIX shell script, which then generates another UNIX shell script, which eventually generates Makefiles. CMake simply generates Makefiles out of CMakeLists.txt files-- much simpler to understand and debug, and much faster. CMake is a lot easier to learn. automake error messages can be very, very confusing. This is because you are essentially debugging a pile of shell scripts and macros, rather than a coherent whole. So you see error messages like "autoreconf: cannot empty /tmp/ar0.4849: Is a directory" or "Can't locate object method "path" via package "Autom4te... and so forth. CMake error messages come from the CMake application and they almost always immediately point you to the problem. >From a build point of view, the net result of adopting CMake would be that you would no longer need automake and related programs installed to build the native parts of Hadoop. Instead, you would need CMake installed. CMake is packaged by Red Hat, even in RHEL5, so it shouldn't be difficult to install locally. It's also available for Mac OS X and Windows, as I mentioned earlier. The JIRA for this work is at https://issues.apache.org/jira/browse/HADOOP-8368 Thanks for reading. sincerely, Colin
