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.\" @(#)strspn.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd May 24, 2014 36.Dt STRSPN 3 37.Os 38.Sh NAME 39.Nm strspn , 40.Nm strcspn 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.Ft size_t 49.Fn strcspn "const char *s" "const char *charset" 50.Sh DESCRIPTION 51The 52.Fn strspn 53function 54spans the initial part of the null-terminated string 55.Fa s 56as long as the characters from 57.Fa s 58occur in the null-terminated string 59.Fa charset . 60In other words, it computes the string array index 61of the first character of 62.Fa s 63which is not in 64.Fa charset , 65else the index of the first null character. 66.Pp 67The 68.Fn strcspn 69function 70spans the initial part of the null-terminated string 71.Fa s 72as long as the characters from 73.Fa s 74do not occur in the null-terminated string 75.Fa charset 76(it 77spans the 78.Em complement 79of 80.Fa charset ) . 81In other words, it computes the string array index 82of the first character of 83.Fa s 84which is also in 85.Fa charset , 86else the index of the first null character. 87.Sh RETURN VALUES 88The 89.Fn strspn 90and 91.Fn strcspn 92functions 93return the number of characters spanned. 94.Sh SEE ALSO 95.Xr memchr 3 , 96.Xr strchr 3 , 97.Xr strpbrk 3 , 98.Xr strrchr 3 , 99.Xr strsep 3 , 100.Xr strstr 3 , 101.Xr strtok 3 , 102.Xr wcsspn 3 103.Sh STANDARDS 104The 105.Fn strspn 106and 107.Fn strcspn 108functions 109conform to 110.St -isoC . 111