On Saturday, 16 August 2025 at 15:14:21 UTC, H. S. Teoh wrote:
On Sat, Aug 16, 2025 at 03:03:21PM +0000, Brother Bill via
Digitalmars-d-learn wrote: [...]
I'm not sure we are on the same page.
My question is whether having a pointer to invalid memory
causes
problems. I am fully aware that reading or writing to an
invalid
memory address causes problems.
I am grasping that even having a pointer pointing to an
invalid memory address is a huge code smell. But will it
cause any undefined behavior merely having a pointer with an
invalid memory address.
What do you mean by "cause any undefined behaviour"? UB is
defined by the language spec, which states that assigning a
non-pointer value (or a random garbage value) to a pointer is
UB. What it actually does at runtime is orthogonal to this.
At the machine level, there is no UB, it's simply following the
instructions you gave it literally. That the results may not
be what you expect is a problem at a higher level of
abstraction.
So a good D developer should not store an invalid pointer address
into a pointer,
with the single exception of storing a pointer address just past
a slice or array.
