How to Log Results VISA Programming Examples
Agilent 8163A/B, 8164A/B & 8166A/B Mainframes, Fifth Edition 211
  {
    ViStatus    errStatus;     /* returned error code from visa call */
    ViSession   defaultRM;     /* default visa resource manager variable 
*/
    /* First get initialized the visa library (see example 1) */ 
    errStatus = viOpenDefaultRM (&defaultRM);
    if (errStatus < VI_SUCCESS) 
          printf("Failed to open VISA Resource manager\n"); 
 
    /* Open session to GPIB device at address 20; */ 
    errStatus = viOpen (defaultRM, "GPIB::20::INSTR",
                         VI_NULL,VI_NULL,iHandle); 
    if (errStatus < VI_SUCCESS) 
          printf("Failed to open instrument\n");
 
    return errStatus;
  }