string/FreeBSD/strsep.3

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  35 .\"     @(#)strsep.3    8.1 (Berkeley) 6/9/93
  36 .\" $FreeBSD: src/lib/libc/string/strsep.3,v 1.14 2004/07/02 23:52:13 ru Exp $
  37 .\"
  38 .Dd June 9, 1993
  39 .Dt STRSEP 3
  40 .Os
  41 .Sh NAME
  42 .Nm strsep
  43 .Nd separate strings
  44 .Sh LIBRARY
  45 .Lb libc
  46 .Sh SYNOPSIS
  47 .In string.h
  48 .Ft char *
  49 .Fn strsep "char **stringp" "const char *delim"
  50 .Sh DESCRIPTION
  51 The
  52 .Fn strsep
  53 function locates, in the string referenced by
  54 .Fa *stringp ,
  55 the first occurrence of any character in the string
  56 .Fa delim
  57 (or the terminating
  58 .Ql \e0
  59 character) and replaces it with a
  60 .Ql \e0 .
  61 The location of the next character after the delimiter character
  62 (or NULL, if the end of the string was reached) is stored in
  63 .Fa *stringp .
  64 The original value of
  65 .Fa *stringp
  66 is returned.
  67 .Pp
  68 An
  69 .Dq empty
  70 field (i.e., a character in the string
  71 .Fa delim
  72 occurs as the first character of
  73 .Fa *stringp )
  74 can be detected by comparing the location referenced by the returned pointer
  75 to
  76 .Ql \e0 .
  77 .Pp
  78 If
  79 .Fa *stringp
  80 is initially
  81 .Dv NULL ,
  82 .Fn strsep
  83 returns
  84 .Dv NULL .
  85 .Sh EXAMPLES
  86 The following uses
  87 .Fn strsep
  88 to parse a string, containing tokens delimited by white space, into an
  89 argument vector:
  90 .Bd -literal -offset indent
  91 char **ap, *argv[10], *inputstring;
  92
  93 for (ap = argv; (*ap = strsep(&inputstring, " \et")) != NULL;)
  94         if (**ap != '\e0')
  95                 if (++ap >= &argv[10])
  96                         break;
  97 .Ed
  98 .Sh SEE ALSO
  99 .Xr memchr 3 ,
 100 .Xr strchr 3 ,
 101 .Xr strcspn 3 ,
 102 .Xr strpbrk 3 ,
 103 .Xr strrchr 3 ,
 104 .Xr strspn 3 ,
 105 .Xr strstr 3 ,
 106 .Xr strtok 3
 107 .Sh HISTORY
 108 The
 109 .Fn strsep
 110 function
 111 is intended as a replacement for the
 112 .Fn strtok
 113 function.
 114 While the
 115 .Fn strtok
 116 function should be preferred for portability reasons (it conforms to
 117 .St -isoC )
 118 it is unable to handle empty fields, i.e., detect fields delimited by
 119 two adjacent delimiter characters, or to be used for more than a single
 120 string at a time.
 121 The
 122 .Fn strsep
 123 function first appeared in
 124 .Bx 4.4 .