1.\" Copyright (c) 2011 The FreeBSD Foundation 2.\" All rights reserved. 3.\" 4.\" This documentation was written by David Chisnall under sponsorship from 5.\" the FreeBSD Foundation. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.\" 30.Dd September 17, 2011 31.Dt DUPLOCALE 3 32.Os 33.Sh NAME 34.Nm duplocale 35.Nd duplicate an locale 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In locale.h 40.Ft locale_t 41.Fn duplocale "locale_t locale" 42.Sh DESCRIPTION 43Duplicates an existing 44.Fa locale_t 45returning a new 46.Fa locale_t 47that refers to the same locale values but has an independent internal state. 48Various functions, such as 49.Xr mblen 3 50require a persistent state. 51These functions formerly used static variables and calls to them from multiple 52threads had undefined behavior. 53They now use fields in the 54.Fa locale_t 55associated with the current thread by 56.Xr uselocale 3 . 57These calls are therefore only thread safe on threads with a unique per-thread 58locale. 59The locale returned by this call must be freed with 60.Xr freelocale 3 . 61.Sh SEE ALSO 62.Xr freelocale 3 , 63.Xr localeconv 3 , 64.Xr newlocale 3 , 65.Xr querylocale 3 , 66.Xr uselocale 3 , 67.Xr xlocale 3 68.Sh STANDARDS 69This function conforms to 70.St -p1003.1-2008 . 71.Sh BUGS 72Ideally, 73.Xr uselocale 3 74should make a copy of the 75.Fa locale_t 76implicitly to ensure thread safety, 77and a copy of the global locale should be installed lazily on each thread. 78The FreeBSD implementation does not do this, 79for compatibility with Darwin. 80