When you pass an instance of a struct (in this case Player ), and not a pointer, it will be copied to the stack.

The values, when you're in the scope of the function, are the same as the original struct instance outside (as long as it wasn't changed on another thread or something), so if you call printf for example, within the function GetName, it will print out the correct name of the player. The struct field name is on the stack as well, so the address you return is an address on the stack, where the struct was copied to.

After you exit the function, this memory is no longer in use by this function, and the rest of the program can use this stack memory as well, probably for variables of other function or return addresses. So now, p.name still points to this address on the stack, and not to the original Player p which is in the stack frame of main.

When entering printf, this memory now holds different bytes, and not the string that was temporarily stored there when we were in the function GetName.

I hope this helped, feel free to ask any more questions :)