duplocale(3p) — Linux manual page


DUPLOCALE(3P)           POSIX Programmer's Manual          DUPLOCALE(3P)

PROLOG         top

       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.

NAME         top

       duplocale — duplicate a locale object

SYNOPSIS         top

       #include <locale.h>

       locale_t duplocale(locale_t locobj);

DESCRIPTION         top

       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.

RETURN VALUE         top

       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.

ERRORS         top

       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.

EXAMPLES         top

   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

           #include <locale.h>

           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().

RATIONALE         top




SEE ALSO         top

       freelocale(3p), newlocale(3p), uselocale(3p)

       The Base Definitions volume of POSIX.1‐2017, locale.h(0p)

COPYRIGHT         top

       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)