Arg< bool > Class Template Reference

#include <cxxtools/arg.h>

List of all members.

Public Member Functions
	Arg (bool def=false)
	Arg (int &argc, char *argv[], char ch, bool def=false)
	Arg (int &argc, char *argv[], const char *str, bool def=false)
bool	set (int &argc, char *argv[], char ch)
bool	set (int &argc, char *argv[], const char *str)
bool	isTrue () const
bool	isFalse () const
	operator bool () const
bool	isSet () const

---

Detailed Description

template<>
class cxxtools::Arg< bool >

specialization for bool.

Often programs need some switches, which are switched on or off. Users just enter a option without parameter.

example:

   Arg<bool> debug(argc, argv, 'd');
   if (debug)
     std::cout << "debug-mode is set" << std::endl;

---

Constructor & Destructor Documentation

Arg

(

bool

def = false

)

default constructor. Initializes value.

Parameters:

def

initial value

Arg	(	int &	argc,
		char *	argv[],
		char	ch,
		bool	def = false
	)

extract parameter.

Parameters:

	argc	1. parameter of main
	argv	2. of main
	ch	optioncharacter
	def	default-value

example:

      Arg<unsigned> offset(argc, argv, 'o', 0);
      unsigned value = offset.getValue();

---

Member Function Documentation

bool set	(	int &	argc,
		char *	argv[],
		char	ch
	)

Use this constructor to extract a bool-parameter.

As a special case options can be grouped. The parameter is recognized also in a argument, which starts with a '-' and contains somewhere the given character.

example:

      Arg<bool> debug(argc, argv, 'd');
      Arg<bool> ignore(argc, argv, 'i');

Arguments debug and ignore are both set when the program is called with:

      prog -id

      prog -i -d

Options can also switched off with a following '-' like this:

      prog -d-

In the program use:

      Arg<bool> debug(argc, argv, 'd');
      if (debug.isSet())
      {
        if (debug)
          std::cout << "you entered -d" << std::endl;
        else
          std::cout << "you entered -d-" << std::endl;
      }
      else
        std::cout << "no -d option given" << std::endl;

This is useful, if a program defaults to some enabled feature, which can be disabled.

bool set	(	int &	argc,
		char *	argv[],
		const char *	str
	)

Setter for long-options.

The option-parameter is defined with a string. This can extract long-options like:

       prog --debug

with

       Arg<bool> debug(argc, argv, "--debug");

bool isTrue

(

)

const

returns true, if options is set.

bool isFalse

(

)

const

returns true, if options is not set.

operator bool

(

)

const

convertable to bool.

bool isSet

(

)

const

returns true, if option is explicitly set