NAME

hpib_pass_ctl − change active controllers on HP-IB

SYNOPSIS

int hpib_pass_ctl (eid, ba)
int eid, ba;

DESCRIPTION

Hpib_pass_ctl passes control of a bus to an inactive controller on that bus.  The inactive  controller becomes the active  controller  of that bus.  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. 

Not all devices  can accept control.  Pass control passes only active control of the bus.  It cannot  pass  system  control  of the bus.  The  specified interface must be the current active  controller but need not be the system  controller.  The pass control  operation  does not suspend your program if the inactive  controller does not take active  control of the bus.  However, the interface is no longer active controller. 

RETURN VALUE

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

ERRORS

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

­[EBADF] 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. 

AUTHOR

Hpib_pass_ctl was developed by the Hewlett-Packard Company. 

Hewlett-Packard Company  —  Version B.1,  April 12, 1993