National Instruments NI-488.2 - Manual (Page 55)

© National Instruments Corporation 5-1 NI-488.2 User Manual
5
Debugging Your Application
This chapter describes several ways to debug your application.
NI Spy
The NI Spy utility monitors NI-488.2 API calls made by NI-488.2
applications. If an application does not have built-in error detection
handling, you can use NI Spy to determine which NI-488.2 call is failing.
For more information about using NI Spy, select Help»Help Topics
in NI Spy or refer to Chapter 6,
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.
Once you know which NI-488.2 call fails, refer to Appendix B, Status
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 .
NI-488.2 Error Codes
The error variable, iberr , is meaningful only when the ERR bit in the
status variable, ibsta , is set. For a detailed description of each error and
possible solutions, refer to Appendix C, Error Codes and Solutions .