#define GETDIFF_FRAME(X, CC, C, pDiff, DIR) \
  func_getdiff_frame_##C(                   \
    X##Block,                               \
    CC##FrameHSize,                         \
    X##RecFrame[pMBInfo[k].mv_field_sel[2][DIR]][DIR] + vector[2][DIR].offset_##C, \
    CC##FrameHSize,                         \
    pDiff + OFF_##X,                        \
    2*BlkStride_##C,                        \
    0, 0, vector[2][DIR].mctype_##C, 0)请问各位达人,这个宏里面的#是干什么用的?