hpib_send_cmnd(3I) — Series 300, 400, 800 Only

NAME

hpib_send_cmnd() − send command bytes over HP-IB

SYNOPSIS

#include <dvio.h>

int hpib_send_cmnd(int eid, const char *ca, int length);

DESCRIPTION

hpib_send_cmnd() sends specified arbitrary bytes of information on the HP-IB with the ATN line asserted, providing a means to configure and control the bus. eid is an entity identifier of an open HP-IB raw bus device file obtained from an open(), dup(), fcntl(), or creat() call. ca is a character pointer to a string of bytes to be written to the HP-IB bus as commands. length is an integer specifying the number of bytes in the string pointed to by ca.

The interface must currently be the active controller in order to send commands over the bus.

Note that for all HP-IB interfaces, both built-in and plug-in, the most significant bit of each byte is overwritten with a parity bit. All commands are written with odd parity.

RETURN VALUE

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

ERRORS

hpib_send_cmnd() fails under 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 currently the active controller.

[ETIMEDOUT] a timeout occurred.

[EACCES] The interface associated with this eid is locked by another process and O_NDELAY is set for this eid (see io_lock(3I)).

[EINVAL] The value specified for length is invalid, either less than or equal to 0 or greater than MAX_HPIB_COMMANDS as defined in <dvio.h>.

DEPENDENCIES

Series 300/400:

EIO is returned if a timeout occurs.

Series 800:

If the interface is not currently the active controller, hpib_send_cmnd() sets errno to [EACCES] instead of [EIO].

AUTHOR

hpib_send_cmnd() was developed by HP.

Museum

Related Articles