Error Conditions; Hpib_Ppollresp_Ctl - HP 9000 Series 300 Tutorials Manual

Error Conditions
If any of the following error conditions is encountered by
hpib_card_ppoll_resp, it returns -1:
• Entity identifier eid does not refer to an HP-IB raw interface file.
• Entity identifier eid does not refer to an open file.
• A timeout occurs.
• The interface associated with this eid is locked by another process and
D_NDELAY
is set for this eid.
• The device cannot respond on the line number specified by response.
To find out which of these conditions caused the error, your program should
check for the following values of errno:
errno Value
EBADF
ENOTTY
Error Condition
eid does not refer to an open file.
eid does not refer to a raw interface file.
ETIMEDOUT A timeout occurred. (EIO on Series 300)
EACCES
EINVAL
The interface associated with this eid was locked by another process
and
D_NDELA Y
was set for this eid.
The device cannot respond on the line number stecified by response.
hpib_ppoILresp_ctl
The subroutine
hpib_ppoll_resp_ctl
is used to control how the HP-IB
interface will respond to the next parallel poll:
• Assert the assigned data line with the previously configured logic sense
if service is required, or
• Place the opposite logic level on the same data line if the interface does
not need to interact with the Active Controller.
Controlling the HP-IB Interface 3-63