NAME

io_speed_ctl − inform system of required transfer speed

SYNOPSIS

int io_speed_ctl (eid, speed);
int eid, speed;

HP-UX COMPATIBILITY

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

Origin: HP

DESCRIPTION

Io_speed_ctl enables you to select the data transfer speed (within the limits of the hardware) for a data path used for a particular interface.  The transfer method (i.e., DMA, fast-handshake) chosen by the system is determined by the speed requirements. 

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.  Speed is an integer specifying the data transfer speed in K-bytes per second (one K-byte equals 1024 bytes). 

DEPENDENCIES

Series 500:
The Series 500 always provides DMA for the fastest possible I/O speed. Therefore, io_speed_ctl(3D) is a nonoperative condition. 

RETURN VALUE

Io_speed_ctl returns 0 if successful, and −1 otherwise. 

DIAGNOSTICS

Io_speed_ctl fails under the following conditions, and sets errno to the value enclosed in square brackets:

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

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

eid does not refer to a device file [ENOTTY]. 

Hewlett-Packard  —  last mod. May 11, 2021