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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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DUPLOCALE(3P) POSIX Programmer's Manual DUPLOCALE(3P)
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.
duplocale — duplicate a locale object
#include <locale.h>
locale_t duplocale(locale_t locobj);
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.
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.
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.
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;
}
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().
None.
None.
freelocale(3p), newlocale(3p), uselocale(3p)
The Base Definitions volume of POSIX.1‐2017, locale.h(0p)
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 DUPLOCALE(3P)
Pages that refer to this page: locale.h(0p), freelocale(3p), newlocale(3p), uselocale(3p)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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