heap/stack memory allocation

[slicedpan]

Hi, just a quick question, when you define local variables inside a branch inside a function, are they allocated on the stack when that function is called, or are they only allocated if the branch executes, on the heap?

some code to clarify:

void somefunc()
{
	int someint; //this is allocated on the stack afaik

	if (somecondition)
	{
		int anotherint; //how is this allocated?
	}
}

[Disch]

AFAIK everything is allocated on the stack when the function is called. However it is initialized when that branch is taken (here that means nothing, but for a complex type like string it could be significant).

The flip side of that is that the compiler might be able to "recycle" stack space as an optimization:

void func()
{
  if(foo)
  {
    int a;
  }
  if(bar)
  {
    int b;
  }
}

Since a and b are never in scope at the same time, the compiler could (in theory) use the same stack space for each of them.

[hamsterman]

Stack, when the function is called. Note, however, that the constructor is only called when the declaration is reached.

[slicedpan]

thanks guys