On 18 Dec 2015, at 17:59, Richard Charles <rcharles...@gmail.com> wrote: > Debugging a linked library without symbols is difficult (bordering on > impossible).
It's not easy, but far from impossible. If you can read assembly, you can usually figure out quite a lot. The debugger will disassemble stack frames for you when you step into them. It would be a little easier for Objective-C code, where all method names are registered publicly, as are class names and a good part of each object's layout. It helps to familiarize oneself with LLDB's commands. Particularly what registers 64-bit apps use to store parameters and how to print them from inside a method call, and how the 'po' command works for printing objects. But for complaints about an invalid context, it sometimes helps to verify that any API you use from the library this error comes from is documented to accept NULL where you pass it NULL. And in this case I'd also print the current CGContext before any calls you make, and ensure that you save and restore your context before and after any calls where you change it, especially if you create your own contexts. And ensure that you retain any contexts that you're keeping around across calls, and verifying that your window is visible and not deferred if you try to draw in it. (This is all assuming you're not making a basic mistake like calling drawRect: directly or (even indirectly) requesting redraws from inside drawRect: If none of this helps, a common occurrence of weird behaviour like this is also sometimes screwing up internal state by using thread-safe API that is not documented to support being used from more than one thread at once, or API that's not safe to use from non-main threads at all, from several threads. Any if that ring a bell? Cheers, -- Uli Kusterer "The Witnesses of TeachText are everywhere..." http://stacksmith.org _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
