дублировать объект локали (duplicate a locale object)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
duplocale — duplicate a locale object
Синопсис (Synopsis)
#include <locale.h>
locale_t duplocale(locale_t locobj);
Описание (Description)
The duplocale() function shall create a duplicate copy of the
locale object referenced by the locobj argument.
If the locobj argument is LC_GLOBAL_LOCALE, duplocale() shall
create a new locale object containing a copy of the global locale
determined by the setlocale() function.
The behavior is undefined if the locobj argument is not a valid
locale object handle.
Возвращаемое значение (Return value)
Upon successful completion, the duplocale() function shall return
a handle for a new locale object. Otherwise, duplocale() shall
return (locale_t)0 and set errno to indicate the error.
Ошибки (Error)
The duplocale() function shall fail if:
ENOMEM There is not enough memory available to create the locale
object or load the locale data.
The following sections are informative.
Примеры (Examples)
Constructing an Altered Version of an Existing Locale Object
The following example shows a code fragment to create a slightly
altered version of an existing locale object. The function takes
a locale object and a locale name and it replaces the LC_TIME
category data in the locale object with that from the named
locale.
#include <locale.h>
...
locale_t
with_changed_lc_time (locale_t obj, const char *name)
{
locale_t retval = duplocale (obj);
if (retval != (locale_t) 0)
{
locale_t changed = newlocale (LC_TIME_MASK, name, retval);
if (changed == (locale_t) 0)
/* An error occurred. Free all allocated resources. */
freelocale (retval);
retval = changed;
}
return retval;
}
Использование в приложениях (Application usage)
The use of the duplocale() function is recommended for situations
where a locale object is being used in multiple places, and it is
possible that the lifetime of the locale object might end before
all uses are finished. Another reason to duplicate a locale
object is if a slightly modified form is needed. This can be
achieved by a call to newlocale() following the duplocale() call.
As with the newlocale() function, handles for locale objects
created by the duplocale() function should be released by a
corresponding call to freelocale().
The duplocale() function can also be used in conjunction with
uselocale((locale_t)0). This returns the locale in effect for
the calling thread, but can have the value LC_GLOBAL_LOCALE.
Passing LC_GLOBAL_LOCALE to functions such as isalnum_l() results
in undefined behavior, but applications can convert it into a
usable locale object by using duplocale().
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
freelocale(3p), newlocale(3p), uselocale(3p)
The Base Definitions volume of POSIX.1‐2017, locale.h(0p)
