Function GrB_Matrix_select_UDT 

pub unsafe extern "C" fn GrB_Matrix_select_UDT(
    C: GrB_Matrix,
    Mask: GrB_Matrix,
    accum: GrB_BinaryOp,
    op: GrB_IndexUnaryOp,
    A: GrB_Matrix,
    y: *const c_void,
    desc: GrB_Descriptor,
) -> GrB_Info