NAME
ttyname(), ttyname_r(), isatty() — find name of a terminal
SYNOPSIS
#include <unistd.h>
char *ttyname(int fildes);
int ttyname_r(int fildes, char *buffer, size_t buflen);
int isatty(int fildes);
DESCRIPTION
ttyname()
returns a pointer to a string containing the null-terminated path name
of the terminal device associated with file descriptor
fildes.
isatty()
returns 1 if
fildes
is associated with a terminal device, 0 otherwise.
Reentrant Interfaces
ttyname_r()
returns the result string in the supplied buffer. The
buffer
is
buflen
characters long and should have space for the name and the terminating
null character. The maximum length of the terminal name is
TTY_NAME_MAX.
RETURN VALUE
ttyname()
returns a
NULL
pointer if
fildes
does not describe a terminal device in directory
/dev.
ttyname_r()
returns a zero upon success and an error number upon failure.
ERRORS
isatty()
and
ttyname()
fail if any of the following conditions are encountered:
- EBADF
The
fildes
argument is invalid.
- ENOTTY
An inappropriate
I/O
control operation has been attempted.
APPLICATION USAGE
The return value for
ttyname()
points to static data
whose content is overwritten by each call.
WARNINGS
For streams ptys,
ttyname()
and
isatty()
do not consider master ptys to be tty
devices. It should also be noted that
ttyname()
returns a pointer to the
master pty name for all master pty devices. This
is a result of device files being linked together.
Users of
ttyname_r()
should also note that the prototype of this function has
changed in this release for conformance with the POSIX.1c Threads
standard.
The old prototype of
ttyname_r()
is supported for
compatibility with existing DCE applications only.
STANDARDS CONFORMANCE
ttyname(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1
ttyname_r(): POSIX.1c
isatty(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1
Printable version
