USELOCALE(3)               POSIX Programmer's Manual              USELOCALE(3)



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NNAAMMEE
       uselocale -- use locale in current thread

SSYYNNOOPPSSIISS
       #include <locale.h>

       locale_t uselocale(locale_t _n_e_w_l_o_c);

DDEESSCCRRIIPPTTIIOONN
       The _u_s_e_l_o_c_a_l_e() function shall set or query the current locale for the
       calling thread.

       The value for the _n_e_w_l_o_c argument shall be one of the following:

        1. A value returned by the _n_e_w_l_o_c_a_l_e() or _d_u_p_l_o_c_a_l_e() functions

        2. The special locale object descriptor LC_GLOBAL_LOCALE

        3. (llooccaallee__tt)0

       If the _n_e_w_l_o_c argument is (llooccaallee__tt)0, the current locale shall not be
       changed; this value can be used to query the current locale setting. If
       the _n_e_w_l_o_c argument is LC_GLOBAL_LOCALE, any thread-local locale for
       the calling thread shall be uninstalled; the thread shall again use the
       global locale as the current locale, and changes to the global locale
       shall affect the thread. Otherwise, the locale represented by _n_e_w_l_o_c
       shall be installed as a thread-local locale to be used as the current
       locale for the calling thread.

       Once the _u_s_e_l_o_c_a_l_e() function has been called to install a thread-local
       locale, the behavior of every interface using data from the current
       locale shall be affected for the calling thread. The current locale for
       other threads shall remain unchanged.

RREETTUURRNN VVAALLUUEE
       Upon successful completion, the _u_s_e_l_o_c_a_l_e() function shall return a
       handle for the thread-local locale that was in use as the current
       locale for the calling thread on entry to the function, or
       LC_GLOBAL_LOCALE if no thread-local locale was in use. Otherwise,
       _u_s_e_l_o_c_a_l_e() shall return (llooccaallee__tt)0 and set _e_r_r_n_o to indicate the
       error.

EERRRROORRSS
       The _u_s_e_l_o_c_a_l_e() function may fail if:

       EEIINNVVAALL _n_e_w_l_o_c is not a valid locale object and is not (llooccaallee__tt)0.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       Unlike the _s_e_t_l_o_c_a_l_e() function, the _u_s_e_l_o_c_a_l_e() function does not
       allow replacing some locale categories only. Applications that need to
       install a locale which differs only in a few categories must use
       _n_e_w_l_o_c_a_l_e() to change a locale object equivalent to the currently used
       locale and install it.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _d_u_p_l_o_c_a_l_e(), _f_r_e_e_l_o_c_a_l_e(), _n_e_w_l_o_c_a_l_e(), _s_e_t_l_o_c_a_l_e()

       The Base Definitions volume of POSIX.1-2017, <<llooccaallee..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                         USELOCALE(3)
