Qt World Summit: Submit your Presentation

Memory allocation

  • Hi! I have a question. When we write "SomeClass obj;" in any function's body it means that memory for our class will be allocated on stack. If some fields have a type of a pointer then memory for these fields will be allocated on heap via new or via initialisation list in/of the constructor and cleared in the destructor at the end of lifetime of that class, but the 4(8)*N (N-number of pointer type fields) bytes (size of a pointer at x86 or x86-64) will nevertheless go to the stack. And here is the core of the question. What happens when we write "SomeClass *p = new SomeClass();" but every field in class is a primitive, an array with predefined size or declared using "SomeClass obj;" syntax? How does storaging go on in this case?

  • Lifetime Qt Champion

    @Tikani said in Memory allocation:

    SomeClass *p = new SomeClass();

    This is heap allocation. That means the complete object will be stored on the heap - it doesn't matter what the content of the object is - it will be allocated on the heap in this case. Only the pointer (p) will be on the stack.

Log in to reply