ctermid(3)						     Library Functions Manual							ctermid(3)

NAME

       ctermid - Generates the pathname for the controlling terminal

LIBRARY

       Standard C Library (libc.so, libc.a)

SYNOPSIS

       #include <stdio.h>

       char *ctermid(	   char *s);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       ctermid():  XPG4, XPG4-UNIX

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Points to the array into which the ctermid() function copies the string representing the pathname.

DESCRIPTION

       The  ctermid()  function  generates  a  string  that,  when  used as a pathname, refers to the current controlling terminal for the current
       process.  If ctermid() returns a pathname, access to the file is not guaranteed.

       The ctermid() function differs from the ttyname() function in that the ttyname() function is supplied a file  descriptor  and  returns  the
       actual  name  of the terminal associated with that file descriptor, while the ctermid() function returns a string (/dev/tty) that refers to
       the terminal if used as a filename. Thus, the ttyname() function is useful only if the process already has at least one file open to a ter-
       minal.

RETURN VALUES

       If the s parameter is not a null pointer, it points to a character array of at least L_ctermid bytes.  The pathname is placed in this array
       and the value of the s parameter is returned.  The symbolic constant L_ctermid is defined in the stdio.h  header  file,	and  has  a  value
       greater than 0 (zero).

       If  the	s  parameter  is a null pointer, the string is stored in an internal static area and the address is returned. The next call to the
       ctermid() function overwrites the contents of the internal static area.

       If the pathname that would refer to the controlling terminal cannot be determined, or if the function is unsuccessful, the ctermid()  func-
       tion returns an empty string.

RELATED INFORMATION

       Functions: ttyname(3)

       Standards: standards(5) delim off

																	ctermid(3)