NAME

io_width_ctl − set width of data path

SYNOPSIS

int io_width_ctl (eid, width)
int eid, width;

HP-UX COMPATIBILITY

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

Origin: HP

Remarks: Io_width_ctl is implemented on the Series 500 only. 

DESCRIPTION

Io_width_ctl enables you to select the width of the data path to be  used for a  particular interface.  Eid is an entity identifier of an open device file obtained from an open(2), dup(2), fcntl(2), or creat(2) call.  Width is an integer specifying the width of the data path in bits. 

The  allowable widths are system and hardware dependent.  An error is  given if an  invalid width is  specified.  Specifying a  width with this function sets the width for all users of the device file associated with the given entity id.  When first opened, the default width is 8 bits. 

HARDWARE DEPENDENCIES

Series 500:
Only widths of 8 and 16 bits are currently supported.

RETURN VALUE

Io_width_ctl returns 0 if successful, and −1 if an error was encountered. 

DIAGNOSTICS

Io_width_ctl 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]. 

the specified width is not supported on this device file [EINVAL]. 

Hewlett-Packard  —  last mod. May 11, 2021