API UnitIsFriend

This function will determine whether two units are friendly to each other (i.e. able to help each other in combat). isFriend = UnitIsFriend("unit","otherunit");

Arguments

 * unit:String - A valid unit.
 * otherunit:String - A valid unit.

Returns

 * IsFriend:Boolean flag - 1 if otherunit is friendly to unit; nil otherwise.

Example
The following snippet outputs a message when the player has a hostile target. if UnitExists("target") and not UnitIsFriend("player", "target") then print(UnitName("target") .. " is evil! Run!"); end