Limiting the player's view?

[CPLJigsoreQuandary]

How can I limit the player's view so that they can look up and down but only so far up or down? Like if you were using a stationary gun.

[snapshot]

You can do this using ACS

while(true)
{
    PrintBold(d:GetActorPitch(0));
    if(GetActorPitch(0)>4000)
    {
        SetActorPitch(0,4000);
    }
    else
    if(GetActorPitch(0)<-4000)
    {
        SetActorPitch(0,-4000);
    }
    delay(1);
}