Webmaster  |  Imprint 

C++ Server Pages

Main  |  License  |  Documentation  |  Download 

Arg Class Template Reference

#include <cxxtools/arg.h>

List of all members.

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

---

Detailed Description

template<typename T>
class cxxtools::Arg< T >

Read and extract commandline parameters from argc/argv.

Programs usually need some parameters. Usually they start with a '-' followed by a single character and optionally a value. Arg<T> extracts these and other parametes.

This default class processes paramters with a value, which defines a input-extractor-operator operator>> (istream&, T&).

Options are removed from the option-list, so programs can easily check after all options are extracted, if there are parameters left.

example:

   int main(int argc, char* argv[])
   {
     cxxtools::Arg<int> option_n(argc, argv, 'n', 0);
     std::cout << "value for -n: " << option_n << endl;
   }

---

Constructor & Destructor Documentation

Arg

(

const T &

def = T()

)

default constructor. Initializes value.

Parameters:

def

initial value

Arg	(	int &	argc,
		char *	argv[],
		char	ch,
		const T &	def = T()
	)

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();

Arg	(	int &	argc,
		char *	argv[],
		const char *	str,
		const T &	def = T()
	)

GNU defines long options starting with "--". This (and more) is supported here. Instead of giving a single option-character, you specify a string.

example:

       Arg<int> option_number(argc, argv, "--number", 0);
       std::cout << "number =" << option_number.getValue() << std::endl;

---

Member Function Documentation

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

extract parameter.

Parameters:

	argc	1. parameter of main
	argv	2. of main
	ch	optioncharacter

example:

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

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

GNU defines long options starting with "--". This (and more) is supported here. Instead of giving a single option-character, you specify a string.

example:

       Arg<int> option_number;
       number.set(argc, argv, "--number");
       std::cout << "number =" << option_number.getValue() << std::endl;

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

Reads next parameter and removes it.

const T& getValue

(

)

const

returns the value.

operator T

(

)

const

returns the value.

Instead of calling getValue() the argument can be converted implicitly.

example:

     void print(int i)
     { std::cout << i << std::endl; }

     int main(int argc, char* argv[])
     {
       cxxtools::Arg<int> value(argc, argv, 'v', 0);
       print(value);   // pass argument as a int to the function
     }

bool isSet

(

)

const

Liefert true zurück, wenn die Option gefunden wurde, also nicht der Default-Wert zum Einsatz kam.

Copyright © 2008 The Tntnet Development Team

Tntnet 1.6