| .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) |
| .\" |
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| .\" Since the Linux kernel and libraries are constantly changing, this |
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| .\" Modified Sat Jul 24 19:51:06 1993 by Rik Faith (faith@cs.unc.edu) |
| .TH CTERMID 3 2021-03-22 "GNU" "Linux Programmer's Manual" |
| .SH NAME |
| ctermid \- get controlling terminal name |
| .SH SYNOPSIS |
| .nf |
| .B #include <stdio.h> |
| .\" POSIX also requires this function to be declared in <unistd.h>, |
| .\" and glibc does so if suitable feature test macros are defined. |
| .PP |
| .BI "char *ctermid(char *" "s" ); |
| .fi |
| .PP |
| .RS -4 |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .RE |
| .PP |
| .BR ctermid (): |
| .nf |
| _POSIX_C_SOURCE |
| .fi |
| .SH DESCRIPTION |
| .BR ctermid () |
| returns a string which is the pathname for the current |
| controlling terminal for this process. |
| If |
| .I s |
| is NULL, |
| a static buffer is used, otherwise |
| .I s |
| points to a buffer used to hold the terminal pathname. |
| The symbolic constant |
| .B L_ctermid |
| is the maximum number of characters in the returned pathname. |
| .SH RETURN VALUE |
| The pointer to the pathname. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR ctermid () |
| T} Thread safety MT-Safe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| POSIX.1-2001, POSIX.1-2008, Svr4. |
| .SH BUGS |
| The returned pathname may not uniquely identify the controlling |
| terminal; it may, for example, be |
| .IR /dev/tty . |
| .PP |
| It is not assured that the program can open the terminal. |
| .\" in glibc 2.3.x, x >= 4, the glibc headers threw an error |
| .\" if ctermid() was given an argument; fixed in 2.4. |
| .SH SEE ALSO |
| .BR ttyname (3) |
