GETOPTX

Section: C Library Functions (3)
Updated: local
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NAME

getoptx - decode command line options

SYNOPSIS

char getoptx(argc, argv, optstring)
  int argc;
  char *argv[];
  char *optstring;
  extern int optind, opterr;
  extern char *optarg;

DESCRIPTION

getoptx returns a character which is either (a) one of the known option characters specified in optstring, (b) a question mark character (?) if the option is unknown or incorrectly specified, or EOF if all options have been returned. If the caller has specified that an option requires or accepts an argument, the string value of the argument is returned in optarg. In the case of an optional argument optarg may point to an empty ("") string.

Format of optstring

optstring contains the values of the option characters which are recognized. In addition any character may be followed by a colon (:) is it requires an argument, or an asterisk (*) if it accepts an optional argument.

Format of the command line

The command line parsed by getoptx consists of the command name, followed by zero or more options separated by blanks, followed by arguments to the command. The options are ended by any of (a) the end of data on the command line, (b) a token which does not start with a hyphen (-), or (c) the special token --.

Using ? as a valid option

Although getoptx returns the ? as an indication of an unknown option, or one used without a required argument, the ? may be included in the optstr so that ? becomes a known option. The effect is that specifying any invalid option will generate an error message, while using -? as an option does not. In either case a ? returned from getoptx can be used to display a usage message.

EXAMPLES

cval = getoptx(argc, argv, "al:sD*");

The options 'a' and 's' are returned without arguments. The option 'l' requires an argument, which may be part of the same command line token as the option (as:~-l40) or as the following token (as:~-c~40). The option 'D' may be immediately followed by an argument, and if there is no argument it must be the last option in the token.

WARNINGS

A warning message is displayed on stderr and the character ? is returned is either (a) an option character not in optstr is found, or (b) a known option which requires an argument does not have one. If the variable opterr is set to zero the warning message will not be displayed.

LIMITATIONS

The characters colon (:) and asterisk (*) may not be option characters.

AUTHOR

Man page by Bill Davidsen (davidsen@crdos1.crd.ge.com). Original getopt source attributed to AT&T public domain version from 1985 UNIFORUM, changes by Bill Davidsen. All original work by Bill Davidsen is hereby placed in the public domain.

Index

NAME

SYNOPSIS

DESCRIPTION

Format of optstring
Format of the command line
Using ? as a valid option

This document was created by man2html, using the manual pages.
Time: 02:52:25 GMT, February 09, 2023