USELOCALE(3) Linux Programmer's Manual USELOCALE(3)
uselocale - set/get the locale for the calling thread
locale_t uselocale(locale_t newloc);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Since glibc 2.10:
_XOPEN_SOURCE >= 700
Before glibc 2.10:
The uselocale() function sets the current locale for the calling
thread, and returns the thread's previously current locale. After a
successful call to uselocale(), any calls by this thread to functions
that depend on the locale will operate as though the locale has been
set to newloc.
The newloc argument can have one of the following values:
A handle returned by a call to newlocale(3) or duplocale(3)
The calling thread's current locale is set to the specified lo-
The special locale object handle LC_GLOBAL_LOCALE
The calling thread's current locale is set to the global locale
determined by setlocale(3).
The calling thread's current locale is left unchanged (and the
current locale is returned as the function result).
On success, uselocale() returns the locale handle that was set by the
previous call to uselocale() in this thread, or LC_GLOBAL_LOCALE if
there was no such previous call. On error, it returns (locale_t) 0,
and sets errno to indicate the cause of the error.
EINVAL newloc does not refer to a valid locale object.
The uselocale() function first appeared in version 2.3 of the GNU C li-
Unlike setlocale(3), uselocale() does not allow selective replacement
of individual locale categories. To employ a locale that differs in
only a few categories from the current locale, use calls to duplo-
cale(3) and newlocale(3) to obtain a locale object equivalent to the
current locale and modify the desired categories in that object.
See newlocale(3) and duplocale(3).
locale(1), duplocale(3), freelocale(3), newlocale(3), setlocale(3), lo-
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Linux 2020-06-09 USELOCALE(3)