macOS outError problems (Hillagas challenge)

[John Baughman]

I'm working the challenge in chapter 18 of creating a document based application to draw ovals. I have a working solution, but only if I ignore the outError in the - (NSData *)dataOfType... and the - (BOOL)readFromData... methods in MyDocument.m as outError is never NULL.

Can anyone explain why this is? I read elsewhere that often this is the result of a bad pointer someplace. If so, or for whatever reason, how do I debug it to find what is offending.

Thanks
John

 

[m3kilpat]

What language are you using? GDB will help if you're using C/C++.

 

[John Baughman]

I am using Objective-C in Xcode

 

[m3kilpat]

I am using Objective-C in Xcode

You can use GDB for that too. If "how can I debug?" is your main question you should be set now. Just search gdb in google. It's not too bad to learn and will be very handy in the future.