# Poco::Util

# class OptionProcessor

Library: Util
Package: Options
Header: Poco/Util/OptionProcessor.h

## Description

An OptionProcessor is used to process the command line arguments of an application.

The process() method takes an argument from the command line. If that argument starts with an option prefix, the argument is further processed. Otherwise, the argument is ignored and false is returned. The argument must match one of the options given in the OptionSet that is passed to the OptionProcessor with the constructor. If an option is part of a group, at most one option of the group can be passed to the OptionProcessor. Otherwise an IncompatibleOptionsException is thrown. If the same option is given multiple times, but the option is not repeatable, a DuplicateOptionException is thrown. If the option is not recognized, a UnexpectedArgumentException is thrown. If the option requires an argument, but none is given, an MissingArgumentException is thrown. If no argument is expected, but one is present, a UnexpectedArgumentException is thrown. If a partial option name is ambiguous, an AmbiguousOptionException is thrown.

The OptionProcessor supports two modes: Unix mode and default mode. In Unix mode, the option prefix is a dash '-'. A dash must be followed by a short option name, or another dash, followed by a (partial) long option name. In default mode, the option prefix is a slash '/', followed by a (partial) long option name. If the special option '--' is encountered in Unix mode, all following options are ignored.

Option arguments can be specified in three ways. If a Unix short option ("-o") is given, the argument directly follows the option name, without any delimiting character or space ("-ovalue"). In default option mode, or if a Unix long option ("--option") is given, the option argument is delimited from the option name with either an equal sign ('=') or a colon (':'), as in "--option=value" or "/option:value". Finally, a required option argument can be specified on the command line after the option, delimited with a space, as in "--option value" or "-o value". The latter only works for required option arguments, not optional ones.

## Member Summary

Member Functions: checkRequired, isUnixStyle, process, setUnixStyle

## Constructors

### OptionProcessor

OptionProcessor(
const OptionSet & options
);

Creates the OptionProcessor, using the given OptionSet.

## Destructor

### ~OptionProcessor

~OptionProcessor();

Destroys the OptionProcessor.

## Member Functions

### checkRequired

void checkRequired() const;

Checks if all required options have been processed.

Does nothing if all required options have been processed. Throws a MissingOptionException otherwise.

### isUnixStyle

bool isUnixStyle() const;

Returns true iff Unix-style option processing is enabled.

### process

bool process(
const std::string & argument,
std::string & optionName,
std::string & optionArg
);

Examines and processes the given command line argument.

If the argument begins with an option prefix, the option is processed and true is returned. The full option name is stored in optionName and the option argument, if present, is stored in optionArg.

If the option does not begin with an option prefix, false is returned.

### setUnixStyle

void setUnixStyle(
bool flag
);

Enables (flag == true) or disables (flag == false) Unix-style option processing.

If Unix-style processing is enabled, options are expected to begin with a single or a double dash ('-' or '--', respectively). A single dash must be followed by a short option name. A double dash must be followed by a (partial) full option name.

If Unix-style processing is disabled, options are expected to begin with a slash ('/'), followed by a (partial) full option name.