towlower, towlower_l - convert a wide character to lowercase

       For an explanation of the terms used in this section, see attributes(7).
       ┌──────────────────────────────────────────────────────────────────────┬───────────────┬────────────────┐
       │ Interface                                                            │ Attribute     │ Value          │
       ├──────────────────────────────────────────────────────────────────────┼───────────────┼────────────────┤
       │ towlower()                                                           │ Thread safety │ MT-Safe locale │
       ├──────────────────────────────────────────────────────────────────────┼───────────────┼────────────────┤
       │ towlower_l()                                                         │ Thread safety │ MT-Safe        │
       └──────────────────────────────────────────────────────────────────────┴───────────────┴────────────────┘

       The  towlower()  function  is  the  wide-character  equivalent  of  the tolower(3) function.  If wc is an
       uppercase wide character, and there exists a lowercase equivalent in the current locale, it  returns  the
       lowercase equivalent of wc.  In all other cases, wc is returned unchanged.

       The towlower_l() function performs the same task, but performs the conversion based on the character type
       information  in  the  locale specified by locale.  The behavior of towlower_l() is undefined if locale is
       the special locale object LC_GLOBAL_LOCALE (see duplocale(3)) or is not a valid locale object handle.

       The argument wc must be representable as a wchar_t and be a valid character in the locale or be the value
       WEOF.

       Standard C library (libc, -lc)

       towlower, towlower_l - convert a wide character to lowercase

       The behavior of these functions depends on the LC_CTYPE category of the locale.

       These functions are not very appropriate for dealing with Unicode characters, because Unicode knows about
       three cases: upper, lower, and title case.

       If wc was convertible to lowercase, towlower() returns its lowercase equivalent; otherwise it returns wc.

iswlower(3), towctrans(3), towupper(3), locale(7)

Linux man-pages 6.9.1                              2024-05-02                                        towlower(3)

towlower()
              C99, POSIX.1-2001 (XSI).  Obsolete in POSIX.1-2008 (XSI).

       towlower_l()
              glibc 2.3.  POSIX.1-2008.

#include<wctype.h>wint_ttowlower(wint_twc);wint_ttowlower_l(wint_twc,locale_tlocale);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       towlower_l():
           Since glibc 2.10:
               _XOPEN_SOURCE >= 700
           Before glibc 2.10:
               _GNU_SOURCE