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.\" 4. 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.\" @(#)strspn.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/string/strspn.3,v 1.10 2007/01/09 00:28:12 imp Exp $ 34.\" $DragonFly: src/lib/libc/string/strspn.3,v 1.2 2003/06/17 04:26:47 dillon Exp $ 35.\" 36.Dd June 4, 1993 37.Dt STRSPN 3 38.Os 39.Sh NAME 40.Nm strspn 41.Nd span a string 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In string.h 46.Ft size_t 47.Fn strspn "const char *s" "const char *charset" 48.Sh DESCRIPTION 49The 50.Fn strspn 51function 52spans the initial part of the null-terminated string 53.Fa s 54as long as the characters from 55.Fa s 56occur in the null-terminated string 57.Fa charset . 58In other words, it computes the string array index in 59.Fa s 60of the first character of 61.Fa s 62which is not in 63.Fa charset , 64else the index of the first null character. 65.Sh RETURN VALUES 66The 67.Fn strspn 68function 69returns the number of characters spanned. 70.Sh SEE ALSO 71.Xr memchr 3 , 72.Xr strchr 3 , 73.Xr strcspn 3 , 74.Xr strpbrk 3 , 75.Xr strrchr 3 , 76.Xr strsep 3 , 77.Xr strstr 3 , 78.Xr strtok 3 79.Sh STANDARDS 80The 81.Fn strspn 82function 83conforms to 84.St -isoC . 85