Measurement Computing GPIB-488 - Manual (Page 75)

Chapter 4 GPIB 488.2 Library Reference
GPIB-488 4-7 Programming Reference Manual
FindLstn
Finds all listeners on the GPIB.
Syntax
C FindLstn(int board, short addresslist[], short
resultlist[], int limit)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR .
limit is an integer which specifies how many address entries can be placed into the
resultlist array. Set to the size of the resultlist array.
Returns
resultlist will contain the addresses of all detected listeners. This array must be large
enough to hold all possible addresses.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA .
iberr will contain an error code, if an error occurred. An ETAB (20) error indicates that more
listeners are present on the GPIB bus than limit will allow to be placed in resultlist . In
this case, ibcnt contains the number of addresses actually placed in resultlist .
Usage Notes
The addresses specified by addresslist are tested to see if a listening device is present. If
a listener is found at a primary address, its address is placed in resultlist . If no listeners
are detected at a primary address, then all secondary addresses associated with that primary
address are tested. If any listeners are detected, their addresses are placed in
resultlist .
You can use this routine to determine how many devices on the network are capable of
listening. Once these devices are detected, they can be identified by their response to
identification request messages.
Example
This example verifies if listening devices are present at GPIB primary addresses 6 and 7 on
Board 0.
C short addresslist[3] = {6,7,NOADDR};
short resultlist[4];
FindLstn(0, addresslist, resultlist, 4);