Question

google produced nothing, so I wanted to ask SO. What does ccp achieve?

Here’s an example of ccpClamp being used in a method.

-(void) moveCamera:(CGPoint)pos
    {
        CGPoint to = ccpClamp(pos, cameraMin, cameraMax);
        to = ccpSub(to, cameraOffset);
        [self.camera setCenterX:to.x centerY:to.y centerZ:0];
        [self.camera setEyeX:to.x eyeY:to.y eyeZ:[CCCamera getZEye]];

        // update hud-level sprites
        [(HudLayer*)[self.parent getChildByTag:kTagHudLayer] moveSprites:[self getCameraPosition]];
    }

Answer 1

The official documentation doesn’t explain what the word clamp means, but
it is used to limit values to a set boundary (low, high).
In your example, it’s equivalent to:

if (pos < cameraMin)
    return cameraMin;
else if (pos > cameraMax)
    return cameraMax;
else
    return pos;

According to dictionary.com, clamp means:

1. a device, usually of some rigid material, for strengthening or supporting objects or fastening them together.
2. an appliance with opposite sides or parts that may be adjusted or brought closer together to hold or compress something.