On Mar 10, 2013 4:52 PM, "Brian Sidebotham" <[email protected]> wrote: > > Hi Guys, > > I have "fixed" the final issue with python scripting on Windows. I've attached a patch which fixes the sigsegv problem I see on Windows. > > I'd like to discuss it so that I can fully understand why this fixes the issue, or if this is simply a kludge that's putting a plaster on a bone break. > > The issue boiled down to the following code in pcbnew_footprint_wizards.cpp: > > /* Time to call the callback */ > arglist = Py_BuildValue( "(i)", aPage ); > result = CallMethod( "GetParameterPageName", arglist ); > Py_DECREF( arglist ); > > There was a SIGSEGV in Py_DECREF( arglist ). In Py_DECREF() the code was breaking in tupledealloc() (in Objects/tupleobject.c). > > The specific issue was in the macro Py_TRASHCAN_SAFE_BEGIN(op) where PyThreadState_GET() returns NULL.
It looks like that null is unexpected. I thought we were seeing a thread context fetch function returning null earlier also, during dll initialization. Might be same underlying problem. Dllmain () function as I recall, was calling a thread context function and coming up dry. See if they are related by common data or variable name of a saved value. Is this "thread local storage" failing? The next line would SIGSEV. > > The PY_BLOCK_THREADS( ) and PY_UNBLOCK_THREADS( ) macro's surrounding the python calls appear to fix the thread state issue. > > I haven't had a chance to look into wxPyBeginBlockThreads() yet to see what's going on. > > The trouble is that I don't really understand what is going on. I could do with someone versed in python extensions explaining the use of the GIL and the PY_BLOCK_THREADS and PY_UNBLOCK_THREADS macros for me so I can understand some more. > > I've also attached a quick image of the footprint wizard working okay. It generates footprints successfully with this patch in place. So at least that's something positive! :D > > I'm interested to understand what is wrong here. Why does Linux (and presumably MAC) work okay without doing this? > > Perhaps the Windows build is broken in some other way that shouldn't be fixed like this? > > At least there is progress. > > Best Regards, Brian. > > > > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : [email protected] > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp >
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