[Solved] std::vector push_back results in access Violation

Question

Dict* test = (Dict*)malloc(sizeof(Dict)); does not do what you think it does.

malloc allocates a block of memory, but does not initialize it. So later on, when you call test->nodes.push_back, you’re calling into uninitialized memory. Undefined behavior. In your case, it crashes.

The solution here is allocate test with new, which will initialize both test and test->nodes.

Dict* test = new Dict;

The even better solution is to ask why test is dynamically allocated to begin with.

Accepted Answer

Dict* test = (Dict*)malloc(sizeof(Dict)); does not do what you think it does.

malloc allocates a block of memory, but does not initialize it. So later on, when you call test->nodes.push_back, you’re calling into uninitialized memory. Undefined behavior. In your case, it crashes.

The solution here is allocate test with new, which will initialize both test and test->nodes.

Dict* test = new Dict;

The even better solution is to ask why test is dynamically allocated to begin with.