Keysight 82357B can't use NI_VISA runtime

     I use Rohde & Schwarz FSEA30 and Keysight  82357B USBGPIB converter. Now there are a few questions

    1， My VISA program can't connection instrument. when use NI_VISA runtime. but use Keysight  IO library it can work.

    2，vireadtofile just only read 4096  bytes.

         I try set readbuf of VISA,

       status = viSetBuf(vi, VI_READ_BUF, 4096) 
       status = viSetBuf(vi, VI_WRITE_BUF, 4096) 

       status = viReadToFile(vi, "D:\YouName.WMF", 4096, retCount)

        but the result still is “#572676淄茪”