Debug Assertion Failed: _CrtIsValidHeapPointer(pUserData)

Question

Sometimes I get this \"Debug Assertion Failed\" error running my Qt project in debug mode (image). I don\'t know where I wrong because the compiler says nothing and

Answer 1

In our case, the program worked perfectly in DEBUG mode and crashed with the similar error trace in RELEASE mode.

In my case, the RELEASE mode was having msvscrtd.dll in the linker definition. We removed it and the issue resolved.

Alternatively, adding /NODEFAULTLIB to the linker command line arguments also resolved the issue.

Answer 2

_CrtIsValidHeapPointerUserData means, that you have a heap corruption, which is noticed by debug heap checker. Suspect everybody who can write any information into any deleted dynamic object. And yes, you'll receive heap corruction not immideately on rewrite occurs, but on the next heap check, which will be performed on any next memory allocation/deallocation. However should be simply tracked by a call stack in single threaded applications.