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.Dd September 17, 2011
.Dt XLOCALE 3
.Os
.Sh NAME
.Nm xlocale
.Nd Thread-safe extended locale support
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In xlocale.h
.Sh DESCRIPTION
The extended locale support includes a set of functions for setting
thread-local locales,
as well convenience functions for performing locale-aware
calls with a specified locale.
.Pp
The core of the xlocale API is the
.Fa locale_t
type.
This is an opaque type encapsulating a locale.
Instances of this can be either set as the locale for a specific thread or
passed directly to the
.Fa _l
suffixed variants of various standard C functions.
Two special
.Fa locale_t
values are available:
.Bl -bullet -offset indent
.It
NULL refers to the current locale for the thread,
or to the global locale if no locale has been set for this thread.
.It
LC_GLOBAL_LOCALE refers to the global locale.
.El
.Pp
The global locale is the locale set with the
.Xr setlocale 3
function.
.Sh SEE ALSO
.Xr duplocale 3 ,
.Xr freelocale 3 ,
.Xr localeconv 3 ,
.Xr newlocale 3 ,
.Xr querylocale 3 ,
.Xr uselocale 3 ,
.Sh CONVENIENCE FUNCTIONS
The xlocale API includes a number of
.Fa _l
suffixed convenience functions.
These are variants of standard C functions
that have been modified to take an explicit
.Fa locale_t
parameter as the final argument or, in the case of variadic functions,
as an additional argument directly before the format string.
Each of these functions accepts either NULL or LC_GLOBAL_LOCALE.
In these functions, NULL refers to the C locale,
rather than the thread's current locale.
If you wish to use the thread's current locale,
then use the unsuffixed version of the function.
.Pp
These functions are exposed by including
.In xlocale.h
.Em after
including the relevant headers for the standard variant.
For example, the
.Xr strtol_l 3
function is exposed by including
.In xlocale.h
after
.In stdlib.h ,
which defines
.Xr strtol 3 .
.Pp
For reference,
a complete list of the locale-aware functions that are available in this form,
along with the headers that expose them, is provided here:
.Bl -tag -width "<monetary.h> "
.It In wctype.h
.Xr iswalnum_l 3 ,
.Xr iswalpha_l 3 ,
.Xr iswcntrl_l 3 ,
.Xr iswctype_l 3 ,
.Xr iswdigit_l 3 ,
.Xr iswgraph_l 3 ,
.Xr iswlower_l 3 ,
.Xr iswprint_l 3 ,
.Xr iswpunct_l 3 ,
.Xr iswspace_l 3 ,
.Xr iswupper_l 3 ,
.Xr iswxdigit_l 3 ,
.Xr towlower_l 3 ,
.Xr towupper_l 3 ,
.Xr wctype_l 3 ,
.It In ctype.h
.Xr digittoint_l 3 ,
.Xr isalnum_l 3 ,
.Xr isalpha_l 3 ,
.Xr isblank_l 3 ,
.Xr iscntrl_l 3 ,
.Xr isdigit_l 3 ,
.Xr isgraph_l 3 ,
.Xr ishexnumber_l 3 ,
.Xr isideogram_l 3 ,
.Xr islower_l 3 ,
.Xr isnumber_l 3 ,
.Xr isphonogram_l 3 ,
.Xr isprint_l 3 ,
.Xr ispunct_l 3 ,
.Xr isrune_l 3 ,
.Xr isspace_l 3 ,
.Xr isspecial_l 3 ,
.Xr isupper_l 3 ,
.Xr isxdigit_l 3 ,
.Xr tolower_l 3 ,
.Xr toupper_l 3
.It In inttypes.h
.Xr strtoimax_l 3 ,
.Xr strtoumax_l 3 ,
.Xr wcstoimax_l 3 ,
.Xr wcstoumax_l 3
.It In langinfo.h
.Xr nl_langinfo_l 3
.It In monetary.h
.Xr strfmon_l 3
.It In stdio.h
.Xr asprintf_l 3 ,
.Xr fprintf_l 3 ,
.Xr fscanf_l 3 ,
.Xr printf_l 3 ,
.Xr scanf_l 3 ,
.Xr snprintf_l 3 ,
.Xr sprintf_l 3 ,
.Xr sscanf_l 3 ,
.Xr vasprintf_l 3 ,
.Xr vfprintf_l 3 ,
.Xr vfscanf_l 3 ,
.Xr vprintf_l 3 ,
.Xr vscanf_l 3 ,
.Xr vsnprintf_l 3 ,
.Xr vsprintf_l 3 ,
.Xr vsscanf_l 3
.It In stdlib.h
.Xr atof_l 3 ,
.Xr atoi_l 3 ,
.Xr atol_l 3 ,
.Xr atoll_l 3 ,
.Xr mblen_l 3 ,
.Xr mbstowcs_l 3 ,
.Xr mbtowc_l 3 ,
.Xr strtod_l 3 ,
.Xr strtof_l 3 ,
.Xr strtol_l 3 ,
.Xr strtold_l 3 ,
.Xr strtoll_l 3 ,
.Xr strtoq_l 3 ,
.Xr strtoul_l 3 ,
.Xr strtoull_l 3 ,
.Xr strtouq_l 3 ,
.Xr wcstombs_l 3 ,
.Xr wctomb_l 3
.It In string.h
.Xr strcoll_l 3 ,
.Xr strxfrm_l 3 ,
.Xr strcasecmp_l 3 ,
.Xr strcasestr_l 3 ,
.Xr strncasecmp_l 3
.It In time.h
.Xr strftime_l 3
.Xr strptime_l 3
.It In wchar.h
.Xr btowc_l 3 ,
.Xr fgetwc_l 3 ,
.Xr fgetws_l 3 ,
.Xr fputwc_l 3 ,
.Xr fputws_l 3 ,
.Xr fwprintf_l 3 ,
.Xr fwscanf_l 3 ,
.Xr getwc_l 3 ,
.Xr getwchar_l 3 ,
.Xr mbrlen_l 3 ,
.Xr mbrtowc_l 3 ,
.Xr mbsinit_l 3 ,
.Xr mbsnrtowcs_l 3 ,
.Xr mbsrtowcs_l 3 ,
.Xr putwc_l 3 ,
.Xr putwchar_l 3 ,
.Xr swprintf_l 3 ,
.Xr swscanf_l 3 ,
.Xr ungetwc_l 3 ,
.Xr vfwprintf_l 3 ,
.Xr vfwscanf_l 3 ,
.Xr vswprintf_l 3 ,
.Xr vswscanf_l 3 ,
.Xr vwprintf_l 3 ,
.Xr vwscanf_l 3 ,
.Xr wcrtomb_l 3 ,
.Xr wcscoll_l 3 ,
.Xr wcsftime_l 3 ,
.Xr wcsnrtombs_l 3 ,
.Xr wcsrtombs_l 3 ,
.Xr wcstod_l 3 ,
.Xr wcstof_l 3 ,
.Xr wcstol_l 3 ,
.Xr wcstold_l 3 ,
.Xr wcstoll_l 3 ,
.Xr wcstoul_l 3 ,
.Xr wcstoull_l 3 ,
.Xr wcswidth_l 3 ,
.Xr wcsxfrm_l 3 ,
.Xr wctob_l 3 ,
.Xr wcwidth_l 3 ,
.Xr wprintf_l 3 ,
.Xr wscanf_l 3
.It In wctype.h
.Xr iswblank_l 3 ,
.Xr iswhexnumber_l 3 ,
.Xr iswideogram_l 3 ,
.Xr iswnumber_l 3 ,
.Xr iswphonogram_l 3 ,
.Xr iswrune_l 3 ,
.Xr iswspecial_l 3 ,
.Xr nextwctype_l 3 ,
.Xr towctrans_l 3 ,
.Xr wctrans_l 3
.It In xlocale.h
.Xr localeconv_l 3
.El
.Sh STANDARDS
The functions
conform to
.St -p1003.1-2008 .
.Sh HISTORY
The xlocale APIs first appeared in Darwin 8.0.
This implementation was written by David Chisnall,
under sponsorship from the FreeBSD Foundation and first appeared in
.Fx 9.1 .
.Sh CAVEATS
The
.Xr setlocale 3
function, and others in the family, refer to the global locale.
Other functions that depend on the locale, however,
will take the thread-local locale if one has been set.
This means that the idiom of setting the locale using
.Xr setlocale 3 ,
calling a locale-dependent function,
and then restoring the locale will not
have the expected behavior if the current thread has had a locale set using
.Xr uselocale 3 .
You should avoid this idiom and prefer to use the
.Fa _l
suffixed versions instead.