ttyname.3

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)ttyname.3	8.1	9/11/90
.TH ttyname 3 
.SH Name
ttyname, isatty, ttyslot \- find terminal name
.SH Syntax
.B char *ttyname(filedes)
.PP
.B isatty(filedes)
.PP
.B ttyslot()
.SH Description
.NXR "ttyname subroutine"
.NXR "isatty subroutine (standard C)"
.NXR "ttyslot subroutine"
.NXA "ttyname subroutine" "ctermid subroutine"
.NXR "terminal" "finding name"
The
.PN ttyname
subroutine
returns a pointer to the null-terminated path name
of the terminal device associated with file descriptor
.I filedes
(this is a system file descriptor and has nothing to do with the
standard I/O FILE typedef).
.PP
The
.PN isatty
subroutine returns 1 if
.I filedes
is associated with a terminal device, 0 otherwise.
.PP
The
.PN ttyslot
subroutine returns the number of the entry in the
.MS ttys 5
file for the control terminal of the current process.
.SH Restrictions
The return value points to static data
whose content is overwritten by each call.
.SH Diagnostics
The
.PN ttyname
subroutine
returns a null pointer (0) if
.I filedes
does not describe a terminal device in directory 
.PN /dev .
.PP
The
.PN ttyslot
subroutine returns 0 if 
.PN /etc/ttys
is inaccessible or if
it cannot determine the control terminal.
.SH Files
/dev/\(**
.br
/etc/ttys
.SH See Also
ioctl(2), ttys(5)