  We present {\tt radpol} - a numerical scheme for integrating multifrequency
polarized radiative transfer equations along rays propagating in a curved
spacetime. The scheme includes radiative processes such as synchrotron
emission, absorption, Faraday rotation and conversion, and, for the first time,
relativistic Compton scatterings including effects of light polarization. The
scheme is fully covariant and is applicable to model radio-$\gamma$-ray
emission and its polarization from, e.g., relativistic jets and accretion flows
onto black holes and other exotic objects described in alternative metric
theories and modeled semi-analytically or with time-dependent
magnetohydrodynamical simulations. We perform a few tests to validate the
implemented numerical algorithms that handle light polarization in curved
spacetime. We demonstrate application of the scheme to model broadband emission
spectra from a relativistically hot, geometrically thick coronal-like inflow
around a supermassive black hole where the disk model is realized in a general
relativistic magnetohydrodynamical simulation.
