string/FreeBSD/strspn.3

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