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.\" 34.Dd May 24, 2014 35.Dt STRSPN 3 36.Os 37.Sh NAME 38.Nm strspn , 39.Nm strcspn 40.Nd span a string 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In string.h 45.Ft size_t 46.Fn strspn "const char *s" "const char *charset" 47.Ft size_t 48.Fn strcspn "const char *s" "const char *charset" 49.Sh DESCRIPTION 50The 51.Fn strspn 52function 53spans the initial part of the null-terminated string 54.Fa s 55as long as the characters from 56.Fa s 57occur in the null-terminated string 58.Fa charset . 59In other words, it computes the string array index 60of the first character of 61.Fa s 62which is not in 63.Fa charset , 64else the index of the first null character. 65.Pp 66The 67.Fn strcspn 68function 69spans the initial part of the null-terminated string 70.Fa s 71as long as the characters from 72.Fa s 73.Sy do not 74occur in the null-terminated string 75.Fa charset 76.Po it spans the 77.Sy complement 78of 79.Fa charset 80.Pc . 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