plucky (3) duplocale.3posix.gz

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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.


NAME
       duplocale — duplicate a locale object


SYNOPSIS
       #include <locale.h>

       locale_t duplocale(locale_t locobj);


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.


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.


ERRORS
       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
   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;
           }


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().


RATIONALE
       None.


FUTURE DIRECTIONS
       None.


SEE ALSO
       freelocale(), newlocale(), uselocale()

       The Base Definitions volume of POSIX.1‐2017, <locale.h>


       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 .