TTYNAME(3) BSD Library Functions Manual TTYNAME(3)
NAME
ttyname, ttyname_r, isatty — get name of associated terminal (tty) from file descriptor
LIBRARY
Standard C Library (libc, −lc)
SYNOPSIS
#include <unistd.h>
char *
ttyname(int fd);
int
ttyname_r(int fd, char *buf, size_t len);
int
isatty(int fd);
DESCRIPTION
These functions operate on file descriptors for terminal type devices.
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 ttyname() function returns the name stored in a static buffer which will be overwritten on subsequent calls. The ttyname_r() function takes a buffer and length as arguments to avoid this problem.
RETURN VALUES
The isatty() function returns 1 if fd refers to a terminal type device; otherwise, it returns 0 and may set errno to indicate the error. The ttyname() function returns the null terminated name if the device is found and isatty() is true; otherwise a NULL pointer is returned. The ttyname_r() function returns 0 if successful. Otherwise an error number is returned.
ERRORS
These functions may fail if:
[EBADF]
The fd argument is not a valid file descriptor.
[ENOTTY]
The file associated with fd is not a terminal.
Additionally, ttyname_r() may fail if:
[ERANGE]
The bufsize argument is smaller than the length of the string to be returned.
SEE ALSO
fdevname(3), ptsname(3), tcgetattr(3), tty(4)
HISTORY
The isatty() and ttyname() functions appeared in Version 7 AT&T UNIX. The ttyname_r() function appeared in FreeBSD 6.0.
BSD July 18, 2014 BSD