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