Measurement Computing GPIB-488 - Manual (Page 13)

Chapter 2 Programming with the GPIB Library
Programming Reference Manual 2-4 GPIB-488
Global Variables
The following global variables are used in all programming languages:
ibsta Status Word
iberr Error Codes
ibcnt , ibcntl Count Variables (short/long)
The iberr variables are briefly explained here. For additional information
about iberr , refer to Appendix C, IBERR .
For additional information about ibcnt and ibcntl , refer to the routines
which return them.
iberr—The Error Variable
If a GPIB error occurs during a routine, its corresponding error code is
returned into the variable
iberr . Possible error codes and their meanings
are listed in Appendix C, IBERR .
ibcnt and ibcntl—Count Variables
These variables contain an integer which describes how many bytes were
actually transferred during a read or write operation.
ibcnt is an integer
value (16-bits wide) and ibcntl is a long integer value (32-bits wide).