Heap corruption: What could the cause be?

Question

I am investigating a crash due to heap corruption. As this issue is non-trivial and involves analyzing the stack and dump results, I have decided to do a code review of files related to the crash.

To be frank, I don't have in-depth knowledge of when the heap could be corrupted.

I would appreciate if you could suggest scenarios which could lead to heap corruption.

Platform: Windows XP

Language: C++

Compiler: VC6

Answer 1

Common scenarios include:

• Writing outside the allocated space of an array (char *stuff = new char[10]; stuff[10] = 3;)
• Casting to the wrong type
• Uninitialized pointers
• Typo error for -> and .
• Typo error when using * and & (or multiple of either)

[EDIT] From the comments, a few more:

• Mixing new [] and new with delete [] and delete
• Missing or incorrect copy-constructors
• Pointer pointing to garbage
• Calling delete multiple times on the same data
• Polymorphic baseclasses without virtual destructors