# FBB::InetAddress(3bobcat)

## Network Byte Order
(libbobcat-dev_6.02.02)

## 2005-2022

## NAME

FBB::InetAddress - Converting between host byte order and network byte order

## SYNOPSIS

#include <bobcat/inetaddress>
Linking option: -lbobcat

## DESCRIPTION

Computers differ their word-byte order, called `endianness'. A little-endian computer has its least significant byte at the byte having the lower address of a two-byte value, whereas a big-endian computer has its least significant byte at at the byte having the higher address of a two-byte value. In order to allow these computers to communicate over over Internet, host byte order was designed. Objects of the class FBB::InetAddress may be used to convert between network byte order and host byte order (and vice versa).

The class only has a few public members. Most members are protected, and FBB::InetAddress is therefore primarily used as a base class from which other classes are derived. In practice there will be little need to construct objects of the class FBB::InetAddress, which is primarily a support class for the FBB socket-classes.

Internally, all data are stored in network byte order.

As the class' constructors depend on the proper functioning of members of the FBB:GetHostent class, the class' objects can only be constructed when the host whose name or address is searched can be resolved by a name resolution process, e.g., bind(1).

Objects of the class FBB::InetAddress store address information about a host in a struct sockaddr_in data member. A struct sockaddr_in is the data type used to represent socket addresses in the Internet namespace. It has the following members:

- sa_family_t sin_family:
  This identifies the address family or format of the socket address. It holds the value AF_INET.
- struct in_addr sin_addr:
  This is the Internet address of the host machine stored as a binary value.
- size_t short int sin_port:
  This field holds the port number.

## NAMESPACE

FBB
All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.

## INHERITS FROM

-

## PROTECTED CONSTRUCTORS

- InetAddress(std::string const &host, uint16_t port):
  This constructor expects a host name or dotted decimal address and and an (size_t) port number, and determines the host's address information. An FBB::Exception exception is thrown if the address could not be determined.
- InetAddress(uint16_t port):
  This constructor constructs the `generic' address information that is used when constructing, e.g. server sockets.
- InetAddress(sockaddr_in const &address):
  This constructor constructs an FBB::InetAddress object from an initialized sockaddr_in object. It is primarily used to promote a sockaddr_in to an FBB::InetAddresss.

The (public) copy and move constructors (and assignment operators) are available.

## MEMBER FUNCTIONS

- uint16_t port() const:
  Accessor returning the object's port value.
- std::string dottedDecimalAddress() const:
  Accessor returning the object's Internet address as a dotted decimal string. If the address could not be determined, an FBB::Exception object is thrown.
- size_t size() const:
  Accessor returning the size of the object's sockaddr_in (address) information.
- sockaddr const *sockaddrPtr() const:
  Accessor returning the pointer to the object's sockaddr data member.
- sockaddr_in const *sockaddr_inPtr() const:
  Accessor returning the pointer to the object's sockaddr_in data member.

## PROTECTED MEMBER FUNCTIONS

- sockaddr *sockaddrPtr():
  This member returns the object's address information as a pointer to a modifiable struct sockaddr. This allows (contrary to the public member having the same name) derived objects to manipulate the object's address information directly.
- sockaddr_in *sockaddr_inPtr():
  This member returns the object's address information as a pointer to a modifiable struct sockaddr_in. This allows (contrary to the public member having the same name) derived objects to manipulate the object's address information directly.

## EXAMPLE

    #include <iostream>

    #include <bobcat/inetaddress>
    #include <bobcat/exception>

    using namespace std;
    using namespace FBB;

    InetAddress X()
    {
        class A: public InetAddress
        {
            public:
            A(uint16_t port)
            :
                InetAddress(port)
            {}
        };

        return A(2000);
    }

    int main(int argc, char **argv)
    try
    {
        InetAddress const &ia = X();

        cout << "A InetAddress was constructed for port " << ia.port() <<
                endl;
        cout << "It has the generic `ANY' address: " <<
                ia.dottedDecimalAddress() << endl;
    }
    catch (exception const &e)
    {
        cout << "Exception: " << e.what() << endl;
    }

## FILES

bobcat/inetaddress - defines the class interface

## SEE ALSO

bind(1), bobcat(7), gethostent(3bobcat), socketbase(3bobcat)

## BUGS

None Reported.

## BOBCAT PROJECT FILES

- https://fbb-git.gitlab.io/bobcat/: gitlab project page;
- bobcat_6.02.02-x.dsc: detached signature;
- bobcat_6.02.02-x.tar.gz: source archive;
- bobcat_6.02.02-x_i386.changes: change log;
- libbobcat1_6.02.02-x_*.deb: debian package containing the libraries;
- libbobcat1-dev_6.02.02-x_*.deb: debian package containing the libraries, headers and manual pages;

## BOBCAT

Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.

## COPYRIGHT

This is free software, distributed under the terms of the GNU General Public License (GPL).

## AUTHOR

Frank B. Brokken (f.b.brokken@rug.nl).