HPIB_SPOLL(3I)
NAME
hpib_spoll − conduct a serial poll on HP-IB bus
SYNOPSIS
int hpib_spoll (eid, ba);
int eid, ba;
DESCRIPTION
Hpib_spoll conducts a serial poll of the specified device. Eid is an entity identifier of an open HP-IB raw bus device file obtained from an open(2), dup(2), fcntl(2), or creat(2) call. Ba is the bus address of the intended device.
Hpib_spoll polls a single device for its response byte. The information stored in the response byte is device specific with the exception of bit 6. If bit 6 of the response byte is set, the addressed device has asserted the SRQ line, and is requesting service. (Note that the least significant bit of the response byte is bit 0.)
Not all devices respond to the serial poll function. Consult the device documentation. Specifying a device that does not support serial polling may cause a timeout error or suspend your program indefinitely. The interface cannot serial poll itself. The interface must be the active controller.
RETURN VALUE
If hpib_spoll is successful, the device response byte is returned in the least significant byte of the return value. Otherwise, −1 is returned, indicating an error.
ERRORS
Hpib_spoll fails under the following circumstances, and sets errno (see errno(2)) to the value in square brackets:
[EBAD] eid does not refer to an open file.
[ENOTTY] eid does not refer to an HP-IB raw bus device file.
[EIO] the interface is not the active controller.
[ETIMEDOUT] the device polled did not respond before timeout.
[EINVAL] ba is the address of the polling interface itself.
[EACCES] The interface associated with this eid is locked by another process and O_NDELAY is set for this eid (see io_lock(3I)).
DEPENDENCIES
Series 300:
EIO is returned if a timeout occurs.
Series 800:
If the interface is not currently the active controller, hpib_spoll sets errno to [EACCES] instead of to [EIO].
AUTHOR
Hpib_spoll was developed by the Hewlett-Packard Company.
SEE ALSO
Hewlett-Packard Company — HP-UX Release 7.0: Sept 1989