wcsnlen - determine the length of a fixed-size wide-character string

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

       The  wcsnlen()  function  is  the  wide-character  equivalent of the strnlen(3) function.  It returns the
       number of wide-characters in the string pointed  to  by  s,  not  including  the  terminating  null  wide
       character  (L'\0'),  but  at  most maxlen wide characters (note: this parameter is not a byte count).  In
       doing this, wcsnlen() looks at only the first maxlen wide characters at s and never beyond s[maxlen-1].

       glibc 2.1.

       Standard C library (libc, -lc)

       wcsnlen - determine the length of a fixed-size wide-character string

       The wcsnlen() function returns wcslen(s), if that is less than maxlen, or maxlen if there is no null wide
       character among the first maxlen wide characters pointed to by s.

strnlen(3), wcslen(3)

Linux man-pages 6.9.1                              2024-06-15                                         wcsnlen(3)

       POSIX.1-2008.

#include<wchar.h>size_twcsnlen(constwchar_ts[.maxlen],size_tmaxlen);

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

       wcsnlen():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _GNU_SOURCE