man3/wcsnlen.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
   2 .\"
   3 .\" SPDX-License-Identifier: GPL-2.0-or-later
   4 .\"
   5 .\" References consulted:
   6 .\"   GNU glibc-2 source code and manual
   7 .\"   Dinkumware C library reference http://www.dinkumware.com/
   8 .\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
   9 .\"
  10 .TH wcsnlen 3 (date) "Linux man-pages (unreleased)"
  11 .SH NAME
  12 wcsnlen \- determine the length of a fixed-size wide-character string
  13 .SH LIBRARY
  14 Standard C library
  15 .RI ( libc ", " \-lc )
  16 .SH SYNOPSIS
  17 .nf
  18 .B #include <wchar.h>
  19 .PP
  20 .BI "size_t wcsnlen(const wchar_t *" s ", size_t " maxlen );
  21 .fi
  22 .PP
  23 .RS -4
  24 Feature Test Macro Requirements for glibc (see
  25 .BR feature_test_macros (7)):
  26 .RE
  27 .PP
  28 .BR wcsnlen ():
  29 .nf
  30     Since glibc 2.10:
  31         _POSIX_C_SOURCE >= 200809L
  32     Before glibc 2.10:
  33         _GNU_SOURCE
  34 .fi
  35 .SH DESCRIPTION
  36 The
  37 .BR wcsnlen ()
  38 function is the wide-character equivalent
  39 of the
  40 .BR strnlen (3)
  41 function.
  42 It returns the number of wide-characters in the string pointed to by
  43 .IR s ,
  44 not including the terminating null wide character (L\(aq\e0\(aq),
  45 but at most
  46 .I maxlen
  47 wide characters (note: this parameter is not a byte count).
  48 In doing this,
  49 .BR wcsnlen ()
  50 looks at only the first
  51 .I maxlen
  52 wide characters at
  53 .I s
  54 and never beyond
  55 .IR s[maxlen\-1] .
  56 .SH RETURN VALUE
  57 The
  58 .BR wcsnlen ()
  59 function returns
  60 .IR wcslen(s) ,
  61 if that is less than
  62 .IR maxlen ,
  63 or
  64 .I maxlen
  65 if there is no null wide character among the
  66 first
  67 .I maxlen
  68 wide characters pointed to by
  69 .IR s .
  70 .SH VERSIONS
  71 The
  72 .BR wcsnlen ()
  73 function is provided in glibc since version 2.1.
  74 .SH ATTRIBUTES
  75 For an explanation of the terms used in this section, see
  76 .BR attributes (7).
  77 .ad l
  78 .nh
  79 .TS
  80 allbox;
  81 lbx lb lb
  82 l l l.
  83 Interface       Attribute       Value
  84 T{
  85 .BR wcsnlen ()
  86 T}      Thread safety   MT-Safe
  87 .TE
  88 .hy
  89 .ad
  90 .sp 1
  91 .SH STANDARDS
  92 POSIX.1-2008.
  93 .SH SEE ALSO
  94 .BR strnlen (3),
  95 .BR wcslen (3)