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TTYNAME(3)             FreeBSD Library Functions Manual             TTYNAME(3)

NAME
     ttyname, ttyname_r, isatty, ttyslot - 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);

     int
     ttyslot(void);

DESCRIPTION
     These functions operate on the system file descriptors for terminal type
     devices.  These descriptors are not related to the standard I/O FILE
     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 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.

     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
     ttyname_r() function returns 0 if successful.  Otherwise an error number
     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

ERRORS
     The ttyname_r() may fail and return the following error codes:

     [ENOTTY]           The fd argument is not a valid file descriptor.

     [ERANGE]           The bufsize argument is smaller than the length of the
                        string to be returned.

SEE ALSO
     ioctl(2), ttys(5)

HISTORY
     The isatty(), ttyname(), and ttyslot() functions appeared in Version 7
     AT&T UNIX.  The ttyname_r() function appeared in FreeBSD 6.0.

FreeBSD 11.0-PRERELEASE          May 14, 2005          FreeBSD 11.0-PRERELEASE

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | FILES | ERRORS | SEE ALSO | HISTORY

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