1 /* 2 * Copyright (c) 1994-2009 Red Hat, Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 11 * 2. Redistributions in binary form must reproduce the above copyright notice, 12 * this list of conditions and the following disclaimer in the documentation 13 * and/or other materials provided with the distribution. 14 * 15 * 3. Neither the name of the copyright holder nor the names of its 16 * contributors may be used to endorse or promote products derived from this 17 * software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 23 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 FUNCTION 34 <<strnlen>>---character string length 35 36 INDEX 37 strnlen 38 39 ANSI_SYNOPSIS 40 #include <string.h> 41 size_t strnlen(const char *<[str]>, size_t <[n]>); 42 43 TRAD_SYNOPSIS 44 #include <string.h> 45 size_t strnlen(<[str]>, <[n]>) 46 char *<[src]>; 47 size_t <[n]>; 48 49 DESCRIPTION 50 The <<strnlen>> function works out the length of the string 51 starting at <<*<[str]>>> by counting chararacters until it 52 reaches a NUL character or the maximum: <[n]> number of 53 characters have been inspected. 54 55 RETURNS 56 <<strnlen>> returns the character count or <[n]>. 57 58 PORTABILITY 59 <<strnlen>> is a GNU extension. 60 61 <<strnlen>> requires no supporting OS subroutines. 62 63 */ 64 65 #undef __STRICT_ANSI__ 66 #include "_ansi.h" 67 #include <string.h> 68 69 size_t 70 _DEFUN (strnlen, (str, n), 71 _CONST char *str _AND 72 size_t n) 73 { 74 _CONST char *start = str; 75 76 while (n-- > 0 && *str) 77 str++; 78 79 return str - start; 80 } 81