C++从内存到流

　//分配一份内存
    HGLOBAL hMem = GlobalAlloc(GMEM_FIXED, a.size());
    //锁定内存
    BYTE* pmem = (BYTE*)GlobalLock(hMem);
    memcpy(pmem,a.begin(),a.size());
    CComPtr<IStream> pstm = NULL;
    CreateStreamOnHGlobal(hMem,FALSE,&pstm);
    Gdiplus::Bitmap* pTileBmp = Gdiplus::Bitmap::FromStream(pstm, false);
    //解锁
    GlobalUnlock(hMem);
    //释放
    GlobalFree(hMem);