The DMG states (p.292):
"Whenever damage reduction completely negates the damage from an attack, it also negates most special effects that accompany the attack, such as injury type poison, monk's stunning or injury inflicted disease."
Example: Rogue with 4d6 sneak hits flanked foe (DR: 10/-) with Medium dagger (dmg. 1d4). Does he
a) ...trigger a sneak attack and deal 1d4+4d6-10 damage?
b) ...deal no damage as sneak attack is a "special effect" negated along with his original damage?
I know this has been answered for Pathfinder but apparently 3.5 rules seem to be different in this regard.