1NEWLOCALE(3) Linux Programmer's Manual NEWLOCALE(3)
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6 newlocale, freelocale - create, modify, and free a locale object
7
9 #include <locale.h>
10 locale_t newlocale(int category_mask, const char *locale,
12 locale_t base);
13 void freelocale(locale_t locobj);
14 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
16 newlocale(), freelocale():
18 Since glibc 2.10:
19 _XOPEN_SOURCE >= 700
20 Before glibc 2.10:
21 _GNU_SOURCE
22
24 The newlocale() function creates a new locale object, or modifies an
25 existing object, returning a reference to the new or modified object as
26 the function result. Whether the call creates a new object or modifies
27 an existing object is determined by the value of base:
28 * If base is (locale_t) 0, a new object is created.
30 * If base refers to valid existing locale object (i.e., an object re‐
32 turned by a previous call to newlocale() or duplocale(3)), then that
33 object is modified by the call. If the call is successful, the con‐
34 tents of base are unspecified (in particular, the object referred to
35 by base may be freed, and a new object created). Therefore, the
36 caller should ensure that it stops using base before the call to
37 newlocale(), and should subsequently refer to the modified object
38 via the reference returned as the function result. If the call
39 fails, the contents of base remain valid and unchanged.
40 If base is the special locale object LC_GLOBAL_LOCALE (see duplo‐
42 cale(3)), or is not (locale_t) 0 and is not a valid locale object han‐
43 dle, the behavior is undefined.
44 The category_mask argument is a bit mask that specifies the locale cat‐
46 egories that are to be set in a newly created locale object or modified
47 in an existing object. The mask is constructed by a bitwise OR of the
48 constants LC_ADDRESS_MASK, LC_CTYPE_MASK, LC_COLLATE_MASK, LC_IDENTIFI‐
49 CATION_MASK, LC_MEASUREMENT_MASK, LC_MESSAGES_MASK, LC_MONETARY_MASK,
50 LC_NUMERIC_MASK, LC_NAME_MASK, LC_PAPER_MASK, LC_TELEPHONE_MASK, and
51 LC_TIME_MASK. Alternatively, the mask can be specified as LC_ALL_MASK,
52 which is equivalent to ORing all of the preceding constants.
53 For each category specified in category_mask, the locale data from lo‐
55 cale will be used in the object returned by newlocale(). If a new lo‐
56 cale object is being created, data for all categories not specified in
57 category_mask is taken from the default ("POSIX") locale.
58 The following preset values of locale are defined for all categories
60 that can be specified in category_mask:
61 "POSIX"
63 A minimal locale environment for C language programs.
64 "C" Equivalent to "POSIX".
66 "" An implementation-defined native environment corresponding to
68 the values of the LC_* and LANG environment variables (see lo‐
69 cale(7)).
70 freelocale()
72 The freelocale() function deallocates the resources associated with lo‐
73 cobj, a locale object previously returned by a call to newlocale() or
74 duplocale(3). If locobj is LC_GLOBAL_LOCALE or is not valid locale ob‐
75 ject handle, the results are undefined.
76 Once a locale object has been freed, the program should make no further
78 use of it.
79
81 On success, newlocale() returns a handle that can be used in calls to
82 duplocale(3), freelocale(), and other functions that take a locale_t
83 argument. On error, newlocale() returns (locale_t) 0, and sets errno
84 to indicate the error.
85
87 EINVAL One or more bits in category_mask do not correspond to a valid
88 locale category.
89 EINVAL locale is NULL.
91 ENOENT locale is not a string pointer referring to a valid locale.
93 ENOMEM Insufficient memory to create a locale object.
95
97 The newlocale() and freelocale() functions first appeared in version
98 2.3 of the GNU C library.
99
101 POSIX.1-2008.
102
104 Each locale object created by newlocale() should be deallocated using
105 freelocale().
106
108 The program below takes up to two command-line arguments, which each
109 identify locales. The first argument is required, and is used to set
110 the LC_NUMERIC category in a locale object created using newlocale().
111 The second command-line argument is optional; if it is present, it is
112 used to set the LC_TIME category of the locale object.
113 Having created and initialized the locale object, the program then ap‐
115 plies it using uselocale(3), and then tests the effect of the locale
116 changes by:
117 1. Displaying a floating-point number with a fractional part. This
119 output will be affected by the LC_NUMERIC setting. In many Euro‐
120 pean-language locales, the fractional part of the number is sepa‐
121 rated from the integer part using a comma, rather than a period.
122 2. Displaying the date. The format and language of the output will be
124 affected by the LC_TIME setting.
125 The following shell sessions show some example runs of this program.
127 Set the LC_NUMERIC category to fr_FR (French):
129 $ ./a.out fr_FR
131 123456,789
132 Fri Mar 7 00:25:08 2014
133 Set the LC_NUMERIC category to fr_FR (French), and the LC_TIME category
135 to it_IT (Italian):
136 $ ./a.out fr_FR it_IT
138 123456,789
139 ven 07 mar 2014 00:26:01 CET
140 Specify the LC_TIME setting as an empty string, which causes the value
142 to be taken from environment variable settings (which, here, specify
143 mi_NZ, New Zealand Māori):
144 $ LC_ALL=mi_NZ ./a.out fr_FR ""
146 123456,789
147 Te Paraire, te 07 o Poutū-te-rangi, 2014 00:38:44 CET
148 Program source
150 #define _XOPEN_SOURCE 700
151 #include <stdio.h>
152 #include <stdlib.h>
153 #include <locale.h>
154 #include <time.h>
155 #define errExit(msg) do { perror(msg); exit(EXIT_FAILURE); \
157 } while (0)
158 int
160 main(int argc, char *argv[])
161 {
162 char buf[100];
163 time_t t;
164 size_t s;
165 struct tm *tm;
166 locale_t loc, nloc;
167 if (argc < 2) {
169 fprintf(stderr, "Usage: %s locale1 [locale2]\n", argv[0]);
170 exit(EXIT_FAILURE);
171 }
172 /* Create a new locale object, taking the LC_NUMERIC settings
174 from the locale specified in argv[1]. */
175 loc = newlocale(LC_NUMERIC_MASK, argv[1], (locale_t) 0);
177 if (loc == (locale_t) 0)
178 errExit("newlocale");
179 /* If a second command-line argument was specified, modify the
181 locale object to take the LC_TIME settings from the locale
182 specified in argv[2]. We assign the result of this newlocale()
183 call to 'nloc' rather than 'loc', since in some cases, we might
184 want to preserve 'loc' if this call fails. */
185 if (argc > 2) {
187 nloc = newlocale(LC_TIME_MASK, argv[2], loc);
188 if (nloc == (locale_t) 0)
189 errExit("newlocale");
190 loc = nloc;
191 }
192 /* Apply the newly created locale to this thread. */
194 uselocale(loc);
196 /* Test effect of LC_NUMERIC. */
198 printf("%8.3f\n", 123456.789);
200 /* Test effect of LC_TIME. */
202 t = time(NULL);
204 tm = localtime(&t);
205 if (tm == NULL)
206 errExit("time");
207 s = strftime(buf, sizeof(buf), "%c", tm);
209 if (s == 0)
210 errExit("strftime");
211 printf("%s\n", buf);
213 /* Free the locale object. */
215 uselocale(LC_GLOBAL_HANDLE); /* So 'loc' is no longer in use */
217 freelocale(loc);
218 exit(EXIT_SUCCESS);
220 }
221
223 locale(1), duplocale(3), setlocale(3), uselocale(3), locale(5), lo‐
224 cale(7)
225
227 This page is part of release 5.12 of the Linux man-pages project. A
228 description of the project, information about reporting bugs, and the
229 latest version of this page, can be found at
230 https://www.kernel.org/doc/man-pages/.
231Linux 2021-03-22 NEWLOCALE(3)