NAME

io_width_ctl − set width of data path

SYNOPSIS

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

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. 

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. 

For the GPIO interface only widths of 8 and 16 bits are currently supported.  For the HP-IB interface only a width of 8 bits is supported. 

RETURN VALUE

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

ERRORS

Io_width_ctl 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 a channel device file. 

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

AUTHOR

Io_width_ctl was developed by HP. 

Hewlett-Packard Company  —  May 11, 2021