Determining When You Are Addressed - HP 9000 Series 300 Tutorials Manual

• A timeout occurred before the condition the routine was waiting for
became true.
• The value specified by status is undefined.
• Entity identifier eid does not refer to a raw HP-IB interface file.
• Entity identifier eid does not refer to an open file.
• The interface associated with this eid is locked by another process and
O_NDELAY
is set for this eid.
• The device is active controller and status specifies
WAIT_FOR_TALKER or WAIT_FOR_LISTENER. (Series
300 only)
To find out which of these conditions caused the error, your program should
check for the following values of errno:
errno Value
EBADF
ENOTTY
EINVAL
Error Condition
eid
does not refer to an open file.
eid
does not refer to a raw HP-IB interface file.
status contains an invalid value.
ETIMEDOUT The specified condition did not become true before a timeout
occurred. (EIO on Series 300)
EACCES
EIO
The interface associated with this
eid
was locked by another process
and
D_NDELAY
was set for this
eid
The device is active controller and status specifies
WAIT_FOR_TALKER or WAIT_FOR_LISTENER (Series 300 only).
Determining When You Are Addressed
As a Non-Active Controller you may be addressed at any time by the current
Active Controller to become a bus talker or listener for data transfer. The DIL
routines hpib_bus_status, hpib_status_wai t, and io_ on_interrupt are
used to determine that the interface is currently being addressed and provide
proper notification to the controlling program.
Controlling the HP-IB Interface 3-67