33f3f40866
Even though POSIX allows us to return simply /dev/tty as a pathname identifying the controlling terminal of the running process, it is nicer if this function were actually useful, by returning the actual pathname of the controlling terminal. Implement ctermid() by using the kern.devname sysctl to resolve the actual name of /dev/tty. Don't use devname(3), since it may return bogus strings like #C:0x123.
109 lines
3.0 KiB
Groff
109 lines
3.0 KiB
Groff
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)ctermid.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd October 1, 2011
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.Dt CTERMID 3
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.Os
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.Sh NAME
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.Nm ctermid
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.Nd generate terminal pathname
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.Ft char *
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.Fn ctermid "char *buf"
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.Ft char *
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.Fn ctermid_r "char *buf"
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.Sh DESCRIPTION
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The
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.Fn ctermid
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function generates a string, that, when used as a pathname, refers to
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the current controlling terminal of the calling process.
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.Pp
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If
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.Fa buf
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is the
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.Dv NULL
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pointer, a pointer to a static area is returned.
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Otherwise, the pathname is copied into the memory referenced by
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.Fa buf .
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The argument
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.Fa buf
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is assumed to be at least
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.Dv L_ctermid
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(as defined in the include
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file
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.In stdio.h )
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bytes long.
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.Pp
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The
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.Fn ctermid_r
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function
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provides the same functionality as
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.Fn ctermid
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except that if
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.Fa buf
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is a
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.Dv NULL
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pointer,
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.Dv NULL
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is returned.
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.Pp
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If no suitable lookup of the controlling terminal name can be performed,
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this implementation returns
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.Ql /dev/tty .
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.Sh RETURN VALUES
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Upon successful completion, a
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.Pf non- Dv NULL
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pointer is returned.
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Otherwise, a
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.Dv NULL
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pointer is returned and the global variable
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The current implementation detects no error conditions.
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.Sh SEE ALSO
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.Xr ttyname 3
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.Sh STANDARDS
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The
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.Fn ctermid
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function conforms to
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.St -p1003.1-88 .
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.Sh BUGS
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By default the
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.Fn ctermid
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function
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writes all information to an internal static object.
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Subsequent calls to
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.Fn ctermid
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will modify the same object.
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