CODEWITHSUNDEEP
c++debugging
vargonian
vargonian

Reputation: 3234

What does it mean if the top of a C++ call stack is "???" with all zeros as the address?

I'm debugging from a crash log (C++, iOS), and I see a call stack that looks like this:

0 ??? 00000000 0 + 0
1 [ModuleName] 0x00130e3b MethodName
2 [ModuleName] 0x004ae417 OtherMethodName
...

Is the top of the call stack hinting at any obvious issue? A null reference, perhaps?

Upvotes: 0

Views: 152

Answers (1)

david.pfx
david.pfx

Reputation: 10853

It means that there is a null pointer on the stack where an address is expected. The null will be decoded to something chosen to draw your attention, not to something that provides any additional information.

So why is there a null on your call stack? Probably because of a stack overwrite in the function called from the previous method. Which of course is why you are debugging a crash dump.

Upvotes: 1

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