Hi, everyone, Thanks for all your help and ideas. I think I have solved this mystery. The symptoms are very misleading and confusing, but the underlying cause turns out to be fairly easy to understand.
The problem is actually related to command line parsing. It turns out that C programs on Mac OS X have access to global variables NXArgc and NXArgv. They are used by one of the system libraries (I think it's CoreFoundation, but I could be wrong) that "eventually" gets loaded when using the xcairo driver. If c_plparseopts is called without the PL_OPT_NODELETE option AND it "deletes" arguments *before* this library gets loaded/initialized, then the program crashes (presumably when the library accesses the modified contents of NXArgv using the unmodified value of NXArgc). If c_plparseopts is called with the PL_OPT_NODELETE option OR if it "deletes" no arguments, OR if it "deletes" arguments *after* this library gets loaded/initialized, then the program does not crash. Using "WITH_FREETYPE=ON" causes the freetype library to be linked in (via `pkg-config --libs plplotd`) to the executable (e.g. x01c), which results in the system library getting loaded/initialized *before* c_plparseopts is called. Using "WITH_FREETYPE=OFF" does not link the freetype library to the executable. In this case, the relevant system library does not get loaded/initialized until *after* c_plparseopts. If c_plparseopts "deletes" command line arguments, then the program will crash (presumably when the library accesses the modified contents of NXArgv using the unmodified value of NXArgc). This can be confirmed by noting that "x01c -dev xcairo" crashes while "PLPLOT_DEV=xcairo x01c" works using the exact same installation. Adding PL_OPT_NODELETE to x01c's call to c_plparseopts also prevents the crash since not "deleting" arguments maintains consistency between NXArgc and the contents of NXArgv. I can think of several ways of preventing this problem: 1. Always include CoreFoundation in linker flags on Macs. 2. Change c_plparseopts to not NULL terminate the modified argv array, but instead point the "extra" elements to an empty string. I've already tried this locally (a two line change) and it works, but it ends up with "argv[argc]" not being a null pointer which violates http://www.open-std.org/jtc1/sc22/WG14/www/docs/n1256.pdf (see section 5.1.2.2.1 item 2). 3a. Add code within "#if define ( __APPLE __)" blocks so that NXArgc can be modified to match the modified contents of NXArgv/argv. This might also an issue on NeXTSTEP, since I think that's where Apple picked up these variables (hence the NX prefix) 3b. Create a cmake test for NXArgc/NXArgv and define a HAVE_NXARGC macro that can be used instead of __APPLE__. I think 3b might be the cleanest option, but I'm open other possibilities (including any I've not listed). Opinions? Thanks again, Dave ------------------------------------------------------------------------------ The Planet: dedicated and managed hosting, cloud storage, colocation Stay online with enterprise data centers and the best network in the business Choose flexible plans and management services without long-term contracts Personal 24x7 support from experience hosting pros just a phone call away. http://p.sf.net/sfu/theplanet-com _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
