On Friday 13 June 2008 10:38:36 you wrote: > On Fre, 2008-06-13 at 08:43 +0200, Alexander Neundorf wrote: ... > > Well, IMO this makes it sound too easy. > > If you write portable software, you have to do platform checks. > > Basically they can be done by > > -checking for the existence of files > > That can be done as - sooner or later - one must install the compiled > stuff anyway. So one has root directory somewhere and one can tell the > tools. Yes. > > -checking if something builds > > -checking the output of running something you just built > > And the above are not really a big problem - "checking if something builds" is no problem, this just works. Running something is a problem, as in "it doesn't just work" (...because you cannot run it). > embedded people usually know such details and can tell the autoconf tools. Basically yes. But if you have a big number of packages (or a huge package) which you didn't write yourself, there will be tests which run executables. Figuring out what all the tests are supposed to test in a complex unknown software project is not trivial. > Even worse is (or at least were) tools like pkg_config and libtool, > which generate directories to the build time library. What do you mean with "generate directories" ? RPATH ? > The only simple solution so far (without diving into the implementation > and searching for root causes) were AFAICS: > - do not use libtool for linking (as the link line as such without > libtool works as expected) Yes, libtool sucks, it's the wrong solution to the problem. (and CMake doesn't use it). > - rewrite generated pkg_config files after generation. > Yes, that's pretty ugly. > But perhaps I was just too dumb to find the correct solutions. Can you please explain ? How do the generated pkg_config files look like ? Ahh, you mean they contain e.g -L/my/build/host/target/environment/opt/foo/lib instead of just -L/opt/foo/lib ? > > The last one is the problem for cross compiling. > > Example: detecting the size of ints > > Why on earth does someone need this explicitly during the build? > If you have portable software, all of that should be hidden in the code > and use "sizeof(int)". >From the "developer of a buildsystem" POV: there will be users who will need it. But this was not the point. My point was: testing something by running an executable can be _a lot_ easier than testing the same without running something. Alex -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
