NAME
gpio_get_status — return status lines of GPIO card
SYNOPSIS
#include <dvio.h>
int gpio_get_status(int eid);
DESCRIPTION
gpio_get_status()
reads the status register of the
GPIO
interface associated with the device file identified by
eid.
eid
is an entity identifier of an open
GPIO
device file obtained from an
open(),
dup(),
fcntl(),
or
creat()
call (see
open(2),
dup(2),
fcntl(2),
or
creat(2)).
The current state of each status line on the interface card
is mapped to the value returned, with
STS0
mapped to the least significant bit.
Only
x
least-significant bits are used, where
x
is the number of status lines available on the hardware interface being used.
DEPENDENCIES
Series 800
For the HP27114A,
x
is 2.
For the HP27114B,
x
is 6.
For the HP28651A,
x
is 5.
RETURN VALUE
gpio_get_status()
returns the value of the status register of the
GPIO
interface associated with
eid,
and -1 if an error was encountered.
ERRORS
gpio_get_status()
fails if any of the following conditions are encountered and sets
errno
accordingly:
- [EBADF]
eid
does not refer to an open file.
- [ENOTTY]
eid
does not refer to a
GPIO
device file.
