Yeah I believe it's a method for Player objects. I'm using Player::setLookLimits(%player, %up, %down). Here's an example of it being used in the default tank:
function armor::onMount(%this,%obj,%col,%slot)
{
Parent::onMount(%this,%obj,%col,%slot);
if(%col.getDataBlock() == TankVehicle.getId())
{
if(%slot $= 2)
{
%obj.setLookLimits(1,0);
}
}
else if(%col.getDataBlock() == TankTurretPlayer.getId())
{
%client = %obj.client;
if(isObject(%client))
ServerCmdUnUseTool(%client);
}
}