HP-UX Reference (11i v2 07/12) - 3 Library Functions A-M (vol 6)

ctermid(3S) ctermid(3S)

NAME

ctermid() - generate ﬁle name for terminal

SYNOPSIS

#include <stdio.h>

char *ctermid(char *s);

DESCRIPTION

ctermid() generates a string that, when used as a pathname, refers to the the controlling terminal for

the current process.

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.

If the process has no controlling terminal, the pathname for the controlling terminal cannot be determined,

or some other error occurs,

ctermid() returns an empty string.

For multi-thread applications, if s is a

NULL pointer, the operation is not performed and a NULL pointer is

returned.

NOTES

The difference between

ctermid() and ttyname() is that ttyname() must be handed a ﬁle descrip-

tor and returns the actual name of the terminal associated with that ﬁle descriptor, while

ctermid()

returns a string (/dev/tty) that refers to the terminal if used as a ﬁle name. (see ttyname(3C)). Thus

ttyname() is useful only if the process already has at least one ﬁle open to a terminal.