The manual tells that it is possible (although without details).
"lines: Output vector of lines. Each line is represented by a 2 or 3 element vector (rho,theta) or (rho,theta,votes) . rho is the distance from the coordinate origin (0,0) (top-left corner of the image). theta is the line rotation angle in radians. votes is the value of accumulator. "
I tried:
vector Vec3f lines
but the program throws an exception.