Re: History of - if(p) delete p; - ... ?

Hi all.

As things are the following works just fine under Visual Studio:

int* p=NULL;
free(p); // If memblock is NULL, the pointer is ignored and free
immediately returns.
delete p; // The default behavior for a null value of _Ptr is to do
nothing.
delete[] p; // The default behavior for a null value of _Ptr is to do
nothing.
p = NULL;

However, our code base uses the following construct basically all the
time:
int* p = ...
if(p)
  free(p); // or delete, or delete[]
p = NULL;

I think the code was initially created on Visual Studio 4 and then got
ported over the years to 5/6/now 2005 ...
I'm trying to figure out why we always used this construct even though
it's not necessary.
Was it *ever* necessary? Pre VC6, pre VC5, ... ?? Has the free function in
C always been specified as noop in case of NULL ?

cheers,
Martin