IABSD.fr/src/lib/libc/stdlib/getsubopt.3

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• Author : jsg
  Date : 2022-08-04 06:20:24
  Hash : 6e23b9dc
  Message : change some 4.4BSD references to earlier releases ok schwarze@

• lib/libc/stdlib/getsubopt.3

• .\" $OpenBSD: getsubopt.3,v 1.16 2022/08/04 06:20:24 jsg Exp $
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  .\"     @(#)getsubopt.3	8.1 (Berkeley) 6/9/93
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  .Dd $Mdocdate: August 4 2022 $
  .Dt GETSUBOPT 3
  .Os
  .Sh NAME
  .Nm getsubopt
  .Nd get sub options from an argument
  .Sh SYNOPSIS
  .In stdlib.h
  .Vt extern char *suboptarg;
  .Ft int
  .Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"
  .Sh DESCRIPTION
  The
  .Fn getsubopt
  function parses a string containing tokens delimited by one or more
  tab, space, or comma
  .Pq Ql \&,
  characters.
  It is intended for use in parsing groups of option arguments provided
  as part of a utility command line.
  .Pp
  The argument
  .Fa optionp
  is a pointer to a pointer to the string.
  The argument
  .Fa tokens
  is a pointer to a
  .Dv NULL Ns -terminated
  array of pointers to strings.
  .Pp
  The
  .Fn getsubopt
  function returns the zero-based offset of the pointer in the
  .Fa tokens
  array referencing a string which matches the first token
  in the string, or \-1 if the string contains no tokens or
  .Fa tokens
  does not contain a matching string.
  .Pp
  If the token is of the form
  .Ar name Ns = Ns Ar value ,
  the location referenced by
  .Fa valuep
  will be set to point to the start of the
  .Dq value
  portion of the token.
  .Pp
  On return from
  .Fn getsubopt ,
  .Fa optionp
  will be set to point to the start of the next token in the string,
  or the NUL at the end of the string if no more tokens are present.
  The comma, space, or tab character ending the token just parsed,
  and the equal sign separating name and value if any, are replaced
  with NUL bytes in the original
  .Pf * Fa optionp
  input string.
  The external variable
  .Fa suboptarg
  will be set to point to the start of the current token, or
  .Dv NULL
  if no tokens were present.
  The argument
  .Fa valuep
  will be set to point to the value portion of the token, or
  .Dv NULL
  if no value portion was present.
  .Sh EXAMPLES
  .Bd -literal
  char *tokens[] = {
  	#define	ONE	0
  		"one",
  	#define	TWO	1
  		"two",
  	NULL
  };
  
  \&...
  
  extern char *optarg, *suboptarg;
  char *options, *value;
  
  while ((ch = getopt(argc, argv, "ab:")) != -1) {
  	switch (ch) {
  	case 'a':
  		/* process "a" option */
  		break;
  	case 'b':
  		options = optarg;
  		while (*options) {
  			switch (getsubopt(&options, tokens, &value)) {
  			case ONE:
  				/* process "one" sub option */
  				break;
  			case TWO:
  				/* process "two" sub option */
  				if (!value)
  					error("no value for two");
  				i = atoi(value);
  				break;
  			case -1:
  				if (suboptarg)
  					error("illegal sub option %s",
  					  suboptarg);
  				else
  					error("missing sub option");
  				break;
  			}
  		}
  		break;
  	}
  }
  .Ed
  .Sh SEE ALSO
  .Xr getopt 3 ,
  .Xr strsep 3
  .Sh STANDARDS
  The
  .Fn getsubopt
  function conforms to
  .St -p1003.1-2008 .
  .Pp
  Allowing space and tab characters to separate tokens
  and the external variable
  .Va suboptarg
  are extensions to that standard.
  .Sh HISTORY
  The
  .Fn getsubopt
  function first appeared in
  .Bx 4.3 Net/2 .