1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)strcspn.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/string/strcspn.3,v 1.9 2007/01/09 00:28:12 imp Exp $ 34.\" $DragonFly: src/lib/libc/string/strcspn.3,v 1.2 2003/06/17 04:26:46 dillon Exp $ 35.\" 36.Dd June 4, 1993 37.Dt STRCSPN 3 38.Os 39.Sh NAME 40.Nm strcspn 41.Nd span the complement of a string 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In string.h 46.Ft size_t 47.Fn strcspn "const char *s" "const char *charset" 48.Sh DESCRIPTION 49The 50.Fn strcspn 51function 52spans the initial part of the null-terminated string 53.Fa s 54as long as the characters from 55.Fa s 56do not occur in string 57.Fa charset 58(it 59spans the 60.Em complement 61of 62.Fa charset ) . 63In other words, it computes the string array index in 64.Fa s 65of the first character of 66.Fa s 67which is also in 68.Fa charset , 69else the index of the first null character. 70.Sh RETURN VALUES 71The 72.Fn strcspn 73function 74returns the number of characters spanned. 75.Sh SEE ALSO 76.Xr memchr 3 , 77.Xr strchr 3 , 78.Xr strpbrk 3 , 79.Xr strrchr 3 , 80.Xr strsep 3 , 81.Xr strspn 3 , 82.Xr strstr 3 , 83.Xr strtok 3 84.Sh STANDARDS 85The 86.Fn strcspn 87function 88conforms to 89.St -isoC . 90