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 file

Answer 1

Every time you do something which isn't defined in the language standard, it is undefined behavior, and one of the ways in which it might manifest itself is through heap corruption. There are about three million ways to do this in C++, so it's really impossible to say.

A few common cases are double-freeing dynamically allocated memory, or writing outside the bounds of an array. Or writing to an uninitialized pointer.

Recent versions of Microsoft's compiler add an /analyze compiler switch which performs a bunch of static analysis to catch such errors. On Linux, valgrind is an obvious choice.

Of course, you are using VC6 which has been unsupported for years, and which has a number of known bugs, resulting in invalid code being generated.

If possible, you should upgrade to a proper compiler.