If you use SetFixedRotation(True) with a Prismatic Joint it crashes
I've tried it myself.
It's not really crashing... It fails with an assertion :
b2Assert(det != 0.0f);
in b2Math.cpp,
b2Vec2 b2Mat33::Solve22(const b2Vec2& b) const
So I'm guessing you shouldn't be setting fixed rotation to a body that is connected to a joint?
Or, maybe it's a bug... :-p
BTW what does Warmstarting and Validate(), and Position Correction do?
They all appear to be methods for testing the integrity of the engine. So not really something you need to be calling. Specifically what they do... I dunno. You'd have to look at the C++ source :-)