Just what are procs, anyway?

[noteventhechair]

When an ogre wields a 2h in one hand, he loses half the procs of the offhand item. What does this mean? What are procs exactly? My necromancer has a shield that promises +30 spellpower; Am I getting +30, +15 or what?

[visage]

What are procs exactly?

"Proc" is a term that originated to describe procedures that are triggered by events. These days, it's more of a generic term that refers to triggered effects. In ToME, things that are procs include: "75 fire damage when this weapon hits", "10% of the time you hit with a spell, cast Dust to Dust automatically", "when you hit an enemy with a bullet, you also hit them with your offhand mindstar", and so on.

When an ogre wields a 2h in one hand, he loses half the procs of the offhand item. What does this mean?

To be precise, Grisly Constitution says "all damage procs from your weapons are reduced by 50%". So, assuming its description is accurate, it only affects damage procs, and only those that are from your weapons. (Any shield you're offhanding should count as a weapon for this purpose, but it also affects your mainhand weapon.

My necromancer has a shield that promises +30 spellpower; Am I getting +30, +15 or what?

A passive stat boost is not a proc, so you're getting the full +30 spellpower.