() function allocates
bytes of space in the stack frame of the
caller. This temporary space is automatically freed on return.
() function returns a pointer to
the beginning of the allocated space.
() function is unsafe because it
cannot ensure that the pointer returned points to a valid and usable block of
memory. The allocation made may exceed the bounds of the stack, or even go
further into other objects in memory, and
() cannot determine such an error.
() with large unbounded