Managing Memory for Game Developers - Learn C++ for Game Development - page 210

The C++ Stack Memory Model
The stack is more difficult to understand. Every time you call a function, the compiler generates code
behind the scenes to allocate memory for the parameters and local variables for the function being
called. Listing 22-1 shows some simple code that we then use to explain how the stack operates.
Listing 22-1. A Simple C++ Program
void function2(int variable1)
{
int variable2{ variable1 };
}
void function1(int variable)
{
function2(variable);
}
int _tmain(int argc, _TCHAR* argv[])
{
int variable{ 0 };
function1(variable);
return 0;
}
The program in Listing 22-1 is very simple: It begins with _tmain , which calls function1 which calls
function2 . Figure 22-1 illustrates what the stack would look like for the main function.
_tmain: variable= 0
Figure 22-1. The stack for _tmain
The stack space for main is very simple. It has a single storage space for the local variable named
variable . These stack spaces for individual functions are known as stack frames . When function1 is
called, a new stack frame is created on top of the existing frame for _tmain . Figure 22-2 shows this
in action.
function1.variable = _tmain.variable
_tmain.variable = 0
Figure 22-2. The added stack frame for function1