define a function returning struct pointer

Question

Please bear with me, i m from other language and newbie to c and learning it from http://c.learncodethehardway.org/book/learn-c-the-hard-way.html

struct Person {         


        

Answer 1

To copy the whole struct and not just pointer is less efficient because a pointer's sizeof is usually much smaller than sizeof of a whole struct itself.

Also, a struct might contain pointers to other data in memory, and blindly copying that could be dangerous for dynamically allocated data (if a code handling one copy would free it, the other copy would be left with invalid pointer).

So shallow copy is almost always a bad idea, unless you're sure that the original goes out of scope - and then why wouldn't you just return a pointer to the struct instead (a struct dynamically allocated on heap of course, so it won't be destroyed like the stack-allocated entities are destroyed, on return from a function).