stdlib/FreeBSD/getsubopt.3

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  28 .\"     @(#)getsubopt.3 8.1 (Berkeley) 6/9/93
  29 .\" $FreeBSD: src/lib/libc/stdlib/getsubopt.3,v 1.11 2007/01/09 00:28:10 imp Exp $
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  31 .Dd June 9, 1993
  32 .Dt GETSUBOPT 3
  33 .Os
  34 .Sh NAME
  35 .Nm getsubopt
  36 .Nd get sub options from an argument
  37 .Sh LIBRARY
  38 .Lb libc
  39 .Sh SYNOPSIS
  40 .In stdlib.h
  41 .Vt extern char *suboptarg ;
  42 .Ft int
  43 .Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"
  44 .Sh DESCRIPTION
  45 The
  46 .Fn getsubopt
  47 function
  48 parses a string containing tokens delimited by one or more tab, space or
  49 comma
  50 .Pq Ql \&,
  51 characters.
  52 It is intended for use in parsing groups of option arguments provided
  53 as part of a utility command line.
  54 .Pp
  55 The argument
  56 .Fa optionp
  57 is a pointer to a pointer to the string.
  58 The argument
  59 .Fa tokens
  60 is a pointer to a
  61 .Dv NULL Ns -terminated
  62 array of pointers to strings.
  63 .Pp
  64 The
  65 .Fn getsubopt
  66 function
  67 returns the zero-based offset of the pointer in the
  68 .Fa tokens
  69 array referencing a string which matches the first token
  70 in the string, or, \-1 if the string contains no tokens or
  71 .Fa tokens
  72 does not contain a matching string.
  73 .Pp
  74 If the token is of the form ``name=value'', the location referenced by
  75 .Fa valuep
  76 will be set to point to the start of the ``value'' portion of the token.
  77 .Pp
  78 On return from
  79 .Fn getsubopt ,
  80 .Fa optionp
  81 will be set to point to the start of the next token in the string,
  82 or the null at the end of the string if no more tokens are present.
  83 The external variable
  84 .Fa suboptarg
  85 will be set to point to the start of the current token, or
  86 .Dv NULL
  87 if no
  88 tokens were present.
  89 The argument
  90 .Fa valuep
  91 will be set to point to the ``value'' portion of the token, or
  92 .Dv NULL
  93 if no ``value'' portion was present.
  94 .Sh EXAMPLES
  95 .Bd -literal -compact
  96 char *tokens[] = {
  97         #define ONE     0
  98                 "one",
  99         #define TWO     1
 100                 "two",
 101         NULL
 102 };
 103
 104 \&...
 105
 106 extern char *optarg, *suboptarg;
 107 char *options, *value;
 108
 109 while ((ch = getopt(argc, argv, "ab:")) != \-1) {
 110         switch(ch) {
 111         case 'a':
 112                 /* process ``a'' option */
 113                 break;
 114         case 'b':
 115                 options = optarg;
 116                 while (*options) {
 117                         switch(getsubopt(&options, tokens, &value)) {
 118                         case ONE:
 119                                 /* process ``one'' sub option */
 120                                 break;
 121                         case TWO:
 122                                 /* process ``two'' sub option */
 123                                 if (!value)
 124                                         error("no value for two");
 125                                 i = atoi(value);
 126                                 break;
 127                         case \-1:
 128                                 if (suboptarg)
 129                                         error("illegal sub option %s",
 130                                           suboptarg);
 131                                 else
 132                                         error("missing sub option");
 133                                 break;
 134                 }
 135                 break;
 136         }
 137 .Ed
 138 .Sh SEE ALSO
 139 .Xr getopt 3 ,
 140 .Xr strsep 3
 141 .Sh HISTORY
 142 The
 143 .Fn getsubopt
 144 function first appeared in
 145 .Bx 4.4 .