wcsnlen(3) — Linux manual page

wcsnlen(3)               Library Functions Manual              wcsnlen(3)

NAME         top

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

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <wchar.h>

       size_t wcsnlen(size_t maxlen;
                      const wchar_t s[maxlen], size_t maxlen);

   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

DESCRIPTION         top

       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].

RETURN VALUE         top

       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.

ATTRIBUTES         top

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

STANDARDS         top

       POSIX.1-2008.

HISTORY         top

       glibc 2.1.

SEE ALSO         top

       strnlen(3), wcslen(3)

COLOPHON         top

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Linux man-pages 6.15            2025-06-28                     wcsnlen(3)

Pages that refer to this page: strlen(3),  wcslen(3),  signal-safety(7)

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