free()

[Brian K. W. Hook]

Okay, I know this is going to be a stupid question to a lot of you, but I
am just a tad curious.  According to the C-reference manuals, you pass
free a pointer to a block of memory that you want deallocate.  Eg.

char *a;

a=malloc(80);
if (a) free(a);

Now what happens if, oh, you do THIS:

foo()
{
int x;

x=10;
if (x) free (&x);
}

I know that malloc uses heap space and that the local variables take up the
stack, so what happens?  &x is NOT null so it will try to free it, so what
happens?  Also, in a similar vein, are global variables allocated on the heap
or stack?  All replies would be appreciated.