In 3.5, players can take the template Necropolitan. This makes them undead, they lose a level, but gain various benefits.
Since undead have no constitution score, what happens to their hit-points during level-up? Does the player simply gain dX + 0?
A related question for pathfinder was answered here, but I am interested in the 3.5 RAW.
From Special Abilities – Nonabilities:
Nonabilities
Some creatures lack certain ability scores. These creatures do not have an ability score of 0 – they lack the ability altogether. The modifier for a nonability is +0. Other effects of nonabilities are detailed below.
(emphasis mine)
So yes, they add class/type HD +0 each level.
Yes, it's dX + 0 at level-up.
As an aside, Improved Toughness will still give you +1 per hit die (Sort of like having a Constitution score of 12). Not to mention getting DM's approval for "being created in a desecrated area/by a Dread Necromancer" can also possibly add some bonus hit points per hit die.
