Chapter 4 Debugging Your Application
NI-488.2 User Manual for Windows 4-2 www.natinst.com
NI Spy records and displays all NI-488.2 calls, as shown in Figure 4-1.
Figure 4-1. NI-488.2 Calls Recorded by NI Spy
For more information about using NI Spy, select HelpยปHelp Topics in
NISpy or refer to Chapter 5, NI Spy Utility.
Global Status Variables
At the end of each NI-488.2 call, the global status variables (ibsta,
iberr, ibcnt, and ibcntl) are updated. If you are developing an
NI-488.2 application, you should check for errors after each NI-488.2 call.
If a NI-488.2 call failed, the high bit of ibsta (the ERR bit) is set. For a
failed NI-488.2 call, iberr contains a value that defines the error. In some
error cases, the value in ibcntl contains even more error information.
You can use NI Spy to determine which NI-488.2 call is failing. Once you
know which NI-488.2 call fails, refer to AppendixB, St atu s Word
Conditions, and Appendix C, Error Codes and Solutions, for help
understanding why the NI-488.2 call failed. This information is also
available in the NI-488.2 online help. For instructions on accessing the
online help, refer to the Using the NI-488.2 Documentation section in
About This Manual.