ctermid(3S)

ctermid -- generate file name for terminal

Synopsis

   #include <stdio.h>
   
   char ctermid(char s);

Description

ctermid generates the path name of the controlling terminal for the current process, and stores it in a string.

If s is a NULL pointer, the string is stored in an internal static area, the contents of which are overwritten at the next call to ctermid, and the address of which is returned. Otherwise, s is assumed to point to a character array of at least L_ctermid elements; the path name is placed in this array and the value of s is returned. The constant L_ctermid is defined in the stdio.h header file.

References

ttyname(3C)

Notices

The difference between ctermid and ttyname(3C) is that ttyname must be handed a file descriptor and returns the actual name of the terminal associated with that file descriptor, while ctermid returns a string (/dev/tty) that will refer to the terminal if used as a file name. Thus ttyname is useful only if the process already has at least one file open to a terminal.

When used by a multi-threaded application, ctermid should have a non-NULL argument.