You can use the
ctermid function to get a file name that you can
use to open the controlling terminal. In the GNU C Library, it returns
the same string all the time:
"/dev/tty". That is a special
“magic” file name that refers to the controlling terminal of the
current process (if it has one). To find the name of the specific
terminal device, use
ttyname; see Is It a Terminal.
ctermid is declared in the header file
Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.
ctermidfunction returns a string containing the file name of the controlling terminal for the current process. If string is not a null pointer, it should be an array that can hold at least
L_ctermidcharacters; the string is returned in this array. Otherwise, a pointer to a string in a static area is returned, which might get overwritten on subsequent calls to this function.
An empty string is returned if the file name cannot be determined for any reason. Even if a file name is returned, access to the file it represents is not guaranteed.
The value of this macro is an integer constant expression that represents the size of a string large enough to hold the file name returned by
See also the
ttyname functions, in
Is It a Terminal.