1.\" 2.\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for 3.\" permission to reproduce portions of its copyrighted documentation. 4.\" Original documentation from The Open Group can be obtained online at 5.\" http://www.opengroup.org/bookstore/. 6.\" 7.\" The Institute of Electrical and Electronics Engineers and The Open 8.\" Group, have given us permission to reprint portions of their 9.\" documentation. 10.\" 11.\" In the following statement, the phrase ``this text'' refers to portions 12.\" of the system documentation. 13.\" 14.\" Portions of this text are reprinted and reproduced in electronic form 15.\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition, 16.\" Standard for Information Technology -- Portable Operating System 17.\" Interface (POSIX), The Open Group Base Specifications Issue 6, 18.\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics 19.\" Engineers, Inc and The Open Group. In the event of any discrepancy 20.\" between these versions and the original IEEE and The Open Group 21.\" Standard, the original IEEE and The Open Group Standard is the referee 22.\" document. The original Standard can be obtained online at 23.\" http://www.opengroup.org/unix/online.html. 24.\" 25.\" This notice shall appear on any product containing this material. 26.\" 27.\" The contents of this file are subject to the terms of the 28.\" Common Development and Distribution License (the "License"). 29.\" You may not use this file except in compliance with the License. 30.\" 31.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 32.\" or http://www.opensolaris.org/os/licensing. 33.\" See the License for the specific language governing permissions 34.\" and limitations under the License. 35.\" 36.\" When distributing Covered Code, include this CDDL HEADER in each 37.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE. 38.\" If applicable, add the following below this CDDL HEADER, with the 39.\" fields enclosed by brackets "[]" replaced with your own identifying 40.\" information: Portions Copyright [yyyy] [name of copyright owner] 41.\" 42.\" 43.\" Copyright 1989 AT&T 44.\" Copyright (c) 1997, The Open Group. All Rights Reserved. 45.\" Portions Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved. 46.\" Copyright 2022 Oxide Computer Company 47.\" 48.Dd February 5, 2022 49.Dt UNLOCKPT 3C 50.Os 51.Sh NAME 52.Nm unlockpt 53.Nd unlock a pseudo-terminal device pair 54.Sh SYNOPSIS 55.In stdlib.h 56.Ft int 57.Fo unlockpt 58.Fa "int fildes" 59.Fc 60.Sh DESCRIPTION 61When a pseudo-terminal manager device is opened, whether through 62.Xr posix_openpt 3C 63or 64.Xr open 2 65on a 66.Xr ptm 4D 67device, the subsidiary device begins operation in a locked state. 68The 69.Fn unlockpt 70function unlocks the pseudo-terminal subsidiary device associated with the 71manager device to which 72.Fa fildes 73refers. 74.Pp 75Portable applications must call 76.Fn unlockpt 77before opening the pseudo-terminal subsidiary device. 78.Sh RETURN VALUES 79.Rv -std unlockpt 80.Sh EXAMPLES 81See 82.Xr posix_openpt 3C 83for an example that includes a call to 84.Fn unlockpt . 85.Sh ERRORS 86The 87.Fn unlockpt 88function may fail if: 89.Bl -tag -width Er 90.It Er EBADF 91The 92.Fa fildes 93argument is not a file descriptor open for writing. 94.It Er EINVAL 95EINVAL 96The 97.Fa fildes 98argument is not associated with a pseudo-terminal manager device. 99.El 100.Sh INTERFACE STABILITY 101.Sy Committed 102.Sh MT LEVEL 103.Sy Safe 104.Sh SEE ALSO 105.Xr open 2 , 106.Xr grantpt 3C , 107.Xr posix_openpt 3C , 108.Xr ptsname 3C , 109.Xr ptm 4D , 110.Xr attributes 7 , 111.Xr standards 7 112