string/strsep.3

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  35 .\"     @(#)strsep.3    8.1 (Berkeley) 6/9/93
  36 .\" $FreeBSD: src/lib/libc/string/strsep.3,v 1.11 2001/10/01 16:09:00 ru Exp $
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  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 ``empty'' field, i.e. one caused by two adjacent delimiter characters,
  69 can be detected by comparing the location referenced by the pointer returned
  70 in
  71 .Fa *stringp
  72 to
  73 .Ql \e0 .
  74 .Pp
  75 If
  76 .Fa *stringp
  77 is initially
  78 .Dv NULL ,
  79 .Fn strsep
  80 returns
  81 .Dv NULL .
  82 .Sh EXAMPLES
  83 The following uses
  84 .Fn strsep
  85 to parse a string, containing tokens delimited by white space, into an
  86 argument vector:
  87 .Bd -literal -offset indent
  88 char **ap, *argv[10], *inputstring;
  89
  90 for (ap = argv; (*ap = strsep(&inputstring, " \et")) != NULL;)
  91         if (**ap != '\e0')
  92                 if (++ap >= &argv[10])
  93                         break;
  94 .Ed
  95 .Sh SEE ALSO
  96 .Xr memchr 3 ,
  97 .Xr strchr 3 ,
  98 .Xr strcspn 3 ,
  99 .Xr strpbrk 3 ,
 100 .Xr strrchr 3 ,
 101 .Xr strspn 3 ,
 102 .Xr strstr 3 ,
 103 .Xr strtok 3
 104 .Sh HISTORY
 105 The
 106 .Fn strsep
 107 function
 108 is intended as a replacement for the
 109 .Fn strtok
 110 function.
 111 While the
 112 .Fn strtok
 113 function should be preferred for portability reasons (it conforms to
 114 .St -isoC )
 115 it is unable to handle empty fields, i.e. detect fields delimited by
 116 two adjacent delimiter characters, or to be used for more than a single
 117 string at a time.
 118 The
 119 .Fn strsep
 120 function first appeared in
 121 .Bx 4.4 .