catching an exception

maxxon · 1st February 2012, 18:25

I was noticing that when catching an exception, the preceeding stack frame locations (lines) prior to the catch are not listed in the exception string.

Is there a reason for this? There are some ideas that I have where it would be useful in having the entre list. Also, it would be great for debugging.

Thanks,

|\/|x

Gavino · 1st February 2012, 19:56

Basically, the error string is built up by the interpreter as the stack unwinds(*) back to the point of the exception handler (try/catch). So it includes all stack frames between those two points, but not any frames enclosing the function that contains the try/catch statement - at that point in the execution, information about those outer frames is not readily available to the parser (whose operation is highly recursive).

(*)This unwinding occurs through a chain of C++ exception handlers.

maxxon · 1st February 2012, 23:14

Ah, that's too bad. It makes for slightly tricker debugging and keeps from determining what line you are currently on for other interesting things.

|\/|x

1st February 2012, 18:25	#1 \| Link
maxxon Registered User Join Date: Jan 2012 Location: On the net Posts: 76	catching an exception I was noticing that when catching an exception, the preceeding stack frame locations (lines) prior to the catch are not listed in the exception string. Is there a reason for this? There are some ideas that I have where it would be useful in having the entre list. Also, it would be great for debugging. Thanks, \|\/\|x Last edited by maxxon; 1st February 2012 at 18:28.

1st February 2012, 19:56	#2 \| Link
Gavino Avisynth language lover Join Date: Dec 2007 Location: Spain Posts: 3,431	Basically, the error string is built up by the interpreter as the stack unwinds() back to the point of the exception handler (try/catch). So it includes all stack frames between those two points, but not any frames enclosing the function that contains the try/catch statement - at that point in the execution, information about those outer frames is not readily available to the parser (whose operation is highly recursive). ()This unwinding occurs through a chain of C++ exception handlers. __________________ GScript and GRunT - complex Avisynth scripting made easier

1st February 2012, 23:14	#3 \| Link
maxxon Registered User Join Date: Jan 2012 Location: On the net Posts: 76	Ah, that's too bad. It makes for slightly tricker debugging and keeps from determining what line you are currently on for other interesting things. \|\/\|x