string/FreeBSD/index.3

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  34 .\"     @(#)index.3     8.1 (Berkeley) 6/4/93
  35 .\" $FreeBSD: src/lib/libc/string/index.3,v 1.11 2003/09/08 19:57:15 ru Exp $
  36 .\"
  37 .Dd June 4, 1993
  38 .Dt INDEX 3
  39 .Os
  40 .Sh NAME
  41 .Nm index , rindex
  42 .Nd locate character in string
  43 .Sh LIBRARY
  44 .Lb libc
  45 .Sh SYNOPSIS
  46 .In strings.h
  47 .Ft "char *"
  48 .Fn index "const char *s" "int c"
  49 .Ft "char *"
  50 .Fn rindex "const char *s" "int c"
  51 .Sh DESCRIPTION
  52 The
  53 .Fn index
  54 function
  55 locates the first occurrence of
  56 .Fa c
  57 (converted to a
  58 .Vt char )
  59 in the string pointed to by
  60 .Fa s .
  61 The terminating null character is considered part of the string;
  62 therefore if
  63 .Fa c
  64 is
  65 .Ql \e0 ,
  66 the functions locate the terminating
  67 .Ql \e0 .
  68 .Pp
  69 The
  70 .Fn rindex
  71 function is identical to
  72 .Fn index ,
  73 except it locates the last occurrence of
  74 .Fa c .
  75 .Sh RETURN VALUES
  76 The functions
  77 .Fn index
  78 and
  79 .Fn rindex
  80 return a pointer to the located character, or
  81 .Dv NULL
  82 if the character does not appear in the string.
  83 .Sh SEE ALSO
  84 .Xr memchr 3 ,
  85 .Xr strchr 3 ,
  86 .Xr strcspn 3 ,
  87 .Xr strpbrk 3 ,
  88 .Xr strrchr 3 ,
  89 .Xr strsep 3 ,
  90 .Xr strspn 3 ,
  91 .Xr strstr 3 ,
  92 .Xr strtok 3
  93 .Sh HISTORY
  94 The
  95 .Fn index
  96 and
  97 .Fn rindex
  98 functions appeared in
  99 .At v6 .
 100 Their prototypes existed previously in
 101 .In string.h
 102 before they were moved to
 103 .In strings.h
 104 for
 105 .St -p1003.1-2001
 106 compliance.