freebsd man page for duplocale

DUPLOCALE(3)						   BSD Library Functions Manual 					      DUPLOCALE(3)

NAME
     duplocale -- duplicate an locale

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <xlocale.h>

     locale_t
     duplocale(locale_t locale);

DESCRIPTION
     Duplicates an existing locale_t returning a new locale_t that refers to the same locale values but has an independent internal state.  Vari-
     ous functions, such as 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 locale_t associated with the current thread by 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 freelocale(3).

SEE ALSO
     freelocale(3), localeconv(3), newlocale(3), querylocale(3), uselocale(3), xlocale(3)

STANDARDS
     This function conforms to IEEE Std 1003.1-2008 (``POSIX.1'').

BUGS
     Ideally, uselocale(3) should make a copy of the 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.

BSD
								September 17, 2011							       BSD