On Sun, Jul 11, 2010 at 05:30:35PM -0400, Schwab,Wilhelm K wrote: > > I am trying to track down a segmentation fault in calling into the Gnu > Scientific Library. These are things that I had working under > Windows+Dolphin and am now trying to do with Pharo and Linux. Offsets to > structure elements and sizes of structures are possible snags, but the calls > that are failing should be reasonably independent of such things: I call the > relevant allocation method and pass along the pointer, so even if my > interpretation of the structs is bogus, I would still expect the functions to > succeed. That is all the more true of new functions that I am adding for > testing purposes. > > The GSL functionality is split into two libraries, and the .so modules appear > to be hobbled on Linux due to circular dependencies between them. A wrapper > .so that is linked to both libraries seems to allow me to call "all" of the > functions (the few I have tried to access) and gives a home for code of my > own. > > I went so far as to compile some GSL sample code, and it does not crash. I > further linked it to my wrapper library and it still works calling the GSL > functions through the wrapper (or at least I *think* that's happening). I > plan to gradually sneak up on the crash by moving things into my library and > then hopefully into Pharo via FFI. > > On Windows, I would use OutputDebugString() to write tracing messages to look > at what is happening until I found the problem. How do you unix VM gurus > tackle such debugging problems? >
Bill, To write strings to output, use fprintf() followed by fflush(). Don't forget the fflush or you'll never figure anything out ;) To use a debugger, compile with CFLAGS=-g (enable debugging info, no compiler optimization), then run the VM under gdb or one of the gui front ends to gdb such as ddd. Put a breakpoint in your function, and you're good to go. Assuming you are using up to date sources from Subversion, run "platforms/unix/configure --help" for more build options. Dave _______________________________________________ Pharo-project mailing list [email protected] http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
