.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) .\" and Copyright 1999 by Bruno Haible (haible@clisp.cons.org) .\" .\" %%%LICENSE_START(VERBATIM) .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" %%%LICENSE_END .\" .\" Modified Sat Jul 24 18:20:12 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Tue Jul 15 16:49:10 1997 by Andries Brouwer (aeb@cwi.nl) .\" Modified Sun Jul 4 14:52:16 1999 by Bruno Haible (haible@clisp.cons.org) .\" Modified Tue Aug 24 17:11:01 1999 by Andries Brouwer (aeb@cwi.nl) .\" Modified Tue Feb 6 03:31:55 2001 by Andries Brouwer (aeb@cwi.nl) .\" .TH SETLOCALE 3 2017-09-15 "GNU" "Linux Programmer's Manual" .SH NAME setlocale \- set the current locale .SH SYNOPSIS .nf .B #include .PP .BI "char *setlocale(int " category ", const char *" locale ); .fi .SH DESCRIPTION The .BR setlocale () function is used to set or query the program's current locale. .PP If .I locale is not NULL, the program's current locale is modified according to the arguments. The argument .I category determines which parts of the program's current locale should be modified. .TS lB lB lB l. Category Governs LC_ALL All of the locale LC_ADDRESS T{ Formatting of addresses and .br geography-related items (*) T} LC_COLLATE String collation LC_CTYPE Character classification LC_IDENTIFICATION Metadata describing the locale (*) LC_MEASUREMENT T{ Settings related to measurements .br (metric versus US customary) (*) T} LC_MESSAGES Localizable natural-language messages LC_MONETARY Formatting of monetary values LC_NAME Formatting of salutations for persons (*) LC_NUMERIC Formatting of nonmonetary numeric values LC_PAPER Settings related to the standard paper size (*) LC_TELEPHONE Formats to be used with telephone services (*) LC_TIME Formatting of date and time values .TE .PP The categories marked with an asterisk in the above table are GNU extensions. For further information on these locale categories, see .BR locale (7). .PP The argument .I locale is a pointer to a character string containing the required setting of .IR category . Such a string is either a well-known constant like "C" or "da_DK" (see below), or an opaque string that was returned by another call of .BR setlocale (). .PP If .I locale is an empty string, .BR """""" , each part of the locale that should be modified is set according to the environment variables. The details are implementation-dependent. For glibc, first (regardless of .IR category ), the environment variable .B LC_ALL is inspected, next the environment variable with the same name as the category (see the table above), and finally the environment variable .BR LANG . The first existing environment variable is used. If its value is not a valid locale specification, the locale is unchanged, and .BR setlocale () returns NULL. .PP The locale .B """C""" or .B """POSIX""" is a portable locale; it exists on all conforming systems. .PP A locale name is typically of the form .IR language "[_" territory "][." codeset "][@" modifier "]," where .I language is an ISO 639 language code, .I territory is an ISO 3166 country code, and .I codeset is a character set or encoding identifier like .B "ISO-8859-1" or .BR "UTF-8" . For a list of all supported locales, try "locale \-a" (see .BR locale (1)). .PP If .I locale is NULL, the current locale is only queried, not modified. .PP On startup of the main program, the portable .B """C""" locale is selected as default. A program may be made portable to all locales by calling: .PP .in +4n .EX setlocale(LC_ALL, ""); .EE .in .PP after program initialization, by using the values returned from a .BR localeconv (3) call for locale-dependent information, by using the multibyte and wide character functions for text processing if .BR "MB_CUR_MAX > 1" , and by using .BR strcoll (3), .BR wcscoll (3) or .BR strxfrm (3), .BR wcsxfrm (3) to compare strings. .SH RETURN VALUE A successful call to .BR setlocale () returns an opaque string that corresponds to the locale set. This string may be allocated in static storage. The string returned is such that a subsequent call with that string and its associated category will restore that part of the process's locale. The return value is NULL if the request cannot be honored. .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lb lb lbw26 l l l. Interface Attribute Value T{ .BR setlocale () T} Thread safety MT-Unsafe const:locale env .TE .sp 1 .SH CONFORMING TO POSIX.1-2001, POSIX.1-2008, C89, C99. .PP The C standards specify only the categories .BR LC_ALL , .BR LC_COLLATE , .BR LC_CTYPE , .BR LC_MONETARY , .BR LC_NUMERIC , and .BR LC_TIME . POSIX.1 adds .BR LC_MESSAGES . The remaining categories are GNU extensions. .SH SEE ALSO .BR locale (1), .BR localedef (1), .BR isalpha (3), .BR localeconv (3), .BR nl_langinfo (3), .BR rpmatch (3), .BR strcoll (3), .BR strftime (3), .BR charsets (7), .BR locale (7) .SH COLOPHON This page is part of release 4.16 of the Linux .I man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at \%https://www.kernel.org/doc/man\-pages/.