freebsd-skq/lib/libc/locale/duplocale.3
gjb 8670397617 General mdoc(7) and typo fixes.
PR:		167734
Submitted by:	Nobuyuki Koganemaru (kogane!jp.freebsd.org)
MFC after:	3 days
2012-05-11 20:06:46 +00:00

80 lines
2.7 KiB
Groff

.\" Copyright (c) 2011 The FreeBSD Foundation
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.\" This documentation was written by David Chisnall under sponsorship from
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.\" $FreeBSD$
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.Dd September 17 2011
.Dt DUPLOCALE 3
.Os
.Sh NAME
.Nm duplocale
.Nd duplicate an locale
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In xlocale.h
.Ft locale_t
.Fn duplocale "locale_t locale"
.Sh DESCRIPTION
Duplicates an existing
.Fa locale_t
returning a new
.Fa locale_t
that refers to the same locale values but has an independent internal state.
Various functions, such as
.Xr mblen 3
require a persistent state.
These functions formerly used static variables and calls to them from multiple
threads had undefined behavior.
They now use fields in the
.Fa locale_t
associated with the current thread by
.Xr uselocale 3 .
These calls are therefore only thread safe on threads with a unique per-thread
locale.
The locale returned by this call must be freed with
.Xr freelocale 3 .
.Sh SEE ALSO
.Xr freelocale 3 ,
.Xr localeconv 3 ,
.Xr newlocale 3 ,
.Xr querylocale 3 ,
.Xr uselocale 3 ,
.Xr xlocale 3
.Sh STANDARDS
This function, conforms to
.St -p1003.1-2008
.Sh BUGS
Ideally,
.Xr uselocale 3
should make a copy of the
.Fa locale_t
implicitly to ensure thread safety,
and a copy of the global locale should be installed lazily on each thread.
The FreeBSD implementation does not do this,
for compatibility with Darwin.