Fix an irrational number $\theta$.
We consider the set of points $y$ such that $\| n \theta - y \| < \varphi(n)$ with general monotone error
functions $\varphi(n)$.
We give an necessary and sufficient condition for the set has full Lebesgue measure and calculate the Hausdorff dimension.
We also consider uniform approximation with an error function $\varphi(n) = n^{-\tau}$.