This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       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                                      TOWLOWER(3POSIX)

       For  towlower():  The  functionality described on this reference page is aligned with the ISO C standard.
       Any conflict between the requirements described here and the ISO C standard is unintentional. This volume
       of POSIX.1‐2017 defers to the ISO C standard.

       The towlower() and towlower_l() functions have as a  domain  a  type  wint_t,  the  value  of  which  the
       application  shall  ensure  is  a  character  representable  as  a  wchar_t,  and  a  wide-character code
       corresponding to a valid character in the locale used by the function or  the  value  of  WEOF.   If  the
       argument  has  any other value, the behavior is undefined.  If the argument of towlower() or towlower_l()
       represents an uppercase wide-character code, and there exists a  corresponding  lowercase  wide-character
       code  as  defined  by  character  type  information in the current locale or in the locale represented by
       locale, respectively (category LC_CTYPE), the result shall be the corresponding lowercase  wide-character
       code.  All other arguments in the domain are returned unchanged.

       The  behavior  is  undefined  if  the  locale  argument  to  towlower_l()  is  the  special locale object
       LC_GLOBAL_LOCALE or is not a valid locale object handle.

       No errors are defined.

       Thefollowingsectionsareinformative.

       None.

       None.

       towlower, towlower_l — transliterate uppercase wide-character code to lowercase

       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.

       None.

       Upon successful completion, the towlower() and towlower_l() functions shall return the  lowercase  letter
       corresponding to the argument passed; otherwise, they shall return the argument unchanged.

setlocale(), uselocale()

       The Base Definitions volume of POSIX.1‐2017, Chapter7, Locale, <locale.h>, <wctype.h>

       #include <wctype.h>

       wint_t towlower(wint_t wc);
       wint_t towlower_l(wint_t wc, locale_t locale);