NAME

hpib_rqst_srvce − allow interface to enable SRQ line on HP-IB

SYNOPSIS

int hpib_rqst_srvce (eid, cv);
int eid, cv;

HP-UX COMPATIBILITY

Level: Device I/O Library − HP-UX/EXTENDED

Origin: HP

DESCRIPTION

Hpib_rqst_srvce specifies  the  response  byte that the interface  sends  when it is  serially  polled by the  active controller.  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.  Cv is an integer control value representation of the desired response byte. 

Hpib_rqst_srvce optionally enables the SRQ line depending  upon the response  byte.  If bit 6 of the response byte is set, the SRQ line is enabled.  It remains enabled until the active  controller  conducts a serial  poll or until the computer  executes the request  function with bit 6 cleared.  The SRQ line  is not  enabled,  however,  as long as the  interface is active  controller.  If bit 6 is set, the  interface remembers its response byte, and enables the SRQ line when control  is passed to  another  device on the bus. 

The response byte looks as follows:

Bit Meaning

 0 SPOLL bit (least significant bit of response byte)

 1 SPOLL bit

 2 SPOLL bit

 3 SPOLL bit

 4 SPOLL bit

 5 SPOLL bit

 6 SRQ line

 7 SPOLL bit (most significant bit of response byte)

HARDWARE DEPENDENCIES

Series 500:
Note that the HP 27110A/B HP-IB interface cards allow only bit 6 to be set.  All other bits are cleared. 

RETURN VALUE

Hpib_rqst_srvce returns 0 (zero) if  successful,  or −1 if an error was encountered. 

DIAGNOSTICS

Hpib_rqst_srvce fails under the following circumstances, and sets errno (see errno(2)) to the value in square brackets:

eid does not refer to an open file [EBADF];

eid does not refer to an HP-IB raw bus device file [ENOTTY]. 

Hewlett-Packard  —  last mod. May 11, 2021