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.Dd May 24, 2014 33.Dt STRSPN 3 34.Os 35.Sh NAME 36.Nm strspn , 37.Nm strcspn 38.Nd span a string 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In string.h 43.Ft size_t 44.Fn strspn "const char *s" "const char *charset" 45.Ft size_t 46.Fn strcspn "const char *s" "const char *charset" 47.Sh DESCRIPTION 48The 49.Fn strspn 50function 51spans the initial part of the null-terminated string 52.Fa s 53as long as the characters from 54.Fa s 55occur in the null-terminated string 56.Fa charset . 57In other words, it computes the string array index 58of the first character of 59.Fa s 60which is not in 61.Fa charset , 62else the index of the first null character. 63.Pp 64The 65.Fn strcspn 66function 67spans the initial part of the null-terminated string 68.Fa s 69as long as the characters from 70.Fa s 71.Sy do not 72occur in the null-terminated string 73.Fa charset 74.Po it spans the 75.Sy complement 76of 77.Fa charset 78.Pc . 79In other words, it computes the string array index 80of the first character of 81.Fa s 82which is also in 83.Fa charset , 84else the index of the first null character. 85.Sh RETURN VALUES 86The 87.Fn strspn 88and 89.Fn strcspn 90functions 91return the number of characters spanned. 92.Sh SEE ALSO 93.Xr memchr 3 , 94.Xr strchr 3 , 95.Xr strpbrk 3 , 96.Xr strrchr 3 , 97.Xr strsep 3 , 98.Xr strstr 3 , 99.Xr strtok 3 , 100.Xr wcsspn 3 101.Sh STANDARDS 102The 103.Fn strspn 104and 105.Fn strcspn 106functions 107conform to 108.St -isoC . 109