freebsd-dev/lib/libc/locale/querylocale.3
Thomas Munro cc7edd258c Add collation version support to querylocale(3).
Provide a way to ask for an opaque version string for a locale_t, so
that potential changes in sort order can be detected.  Similar to
ICU's ucol_getVersion() and Windows' GetNLSVersionEx(), this API is
intended to allow databases to detect when text order-based indexes
might need to be rebuilt.

The CLDR version is extracted from CLDR source data by the Makefile
under tools/tools/locale, written into the machine-generated Makefile
under shared/colldef, passed to localedef -V, and then written into
LC_COLLATE file headers.  The initial version is 34.0.
tools/tools/locale was recently updated to pull down 35.0, but the
output hasn't been committed under share/colldef yet, so that will
provide the first observable change when it happens.  Other versioning
schemes are possible in future, because the format is unspecified.

Reviewed by:	bapt, 0mp, kib, yuripv (albeit a long time ago)
Differential Revision:	https://reviews.freebsd.org/D17166
2020-11-08 02:50:34 +00:00

75 lines
2.7 KiB
Groff

.\" Copyright (c) 2011 The FreeBSD Foundation
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.Dd November 8, 2020
.Dt QUERYLOCALE 3
.Os
.Sh NAME
.Nm querylocale
.Nd Look up the locale name or version for a specified category
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In locale.h
.Ft const char *
.Fn querylocale "int mask" "locale_t locale"
.Sh DESCRIPTION
Returns the name or version of the locale for the category specified by
.Fa mask .
The possible values for the mask are the same as those in
.Xr newlocale 3 ,
when requesting the locale name.
Specify the bitwise OR of
.Fa LC_VERSION_MASK
and another mask value to request a version string.
Version strings can be compared to detect changes to the locale's definition.
The structure of the version string is unspecified.
Currently, version information is only available for
.Fa LC_COLLATE_MASK ,
and an empty string is returned for other categories.
If more than one bit in the mask is set, not counting
.Fa LC_VERSION_MASK ,
the returned value is undefined.
.Sh SEE ALSO
.Xr duplocale 3 ,
.Xr freelocale 3 ,
.Xr localeconv 3 ,
.Xr newlocale 3 ,
.Xr uselocale 3 ,
.Xr xlocale 3
.Sh HISTORY
The
.Fn querylocale
function first appeared in
.Fx 9.1 ,
and is based on the function of the same name in Darwin.
.Fa LC_VERSION_MASK
first appeared in
.Fx 13.0 .