NAME
ttyname, isatty,
ttyslot —
get name of associated terminal (tty)
from file descriptor
SYNOPSIS
#include
<unistd.h>
char *
ttyname(int
fd);
int
isatty(int
fd);
int
ttyslot();
DESCRIPTION
These functions operate on the system file descriptors for terminal type devices. These descriptors are not related to the standard I/OFILE typedef, but refer to the special device files
found in /dev and named
/dev/ttyxx
and for which an entry exists in the initialization file
/etc/ttys. (See
ttys(5).)
The
isatty()
function determines if the file descriptor fd refers
to a valid terminal type device.
The
ttyname()
function gets the related device name of a file descriptor for which
isatty() is true
The
ttyslot()
function fetches the current process' control terminal number from the
ttys(5) file entry.
RETURN VALUES
The ttyname() function returns the null
terminated name if the device is found and isatty()
is true; otherwise a NULL pointer is returned.
The ttyslot() function returns the unit
number of the device file if found; otherwise the value zero is
returned.
FILES
- /dev/∗
- /etc/ttys
SEE ALSO
HISTORY
A isatty(),
ttyname(), and ttyslot()
function appeared in Version 7 AT&T
UNIX.
BUGS
The ttyname() function leaves its result
in an internal static object and returns a pointer to that object.
Subsequent calls to ttyname() will modify the same
object.