TTYNAME(3) MachTen Programmer’s Manual TTYNAME(3)

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/O FILE type-
def, 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 num-
ber 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
ioctl(2), ttys(5)

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 mod-
ify the same object.

4.4BSD June 4, 1993 1