gimite/socket

Overview

C++ library which performs communication using TCP/IP and UDP/IP. It supports Windows (using Winsock2) and UNIX (using POSIX Socket).

• Download
• Notes
• Examples
• Global functions
• socket_stream
• server_stream_socket
• datagram_socket
• ip_address
• socket_address
• Typedefs
• History
• Contact

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gimite/socket.h Ver.1.5

Notes

1. Some Windows headers includes Winsock.h internally, which causes compiler error. In this case, including Winsock2.h before the header will do the trick.
2. GCC 2.9x or before is not supported because interface of streambuf is incompatible.

Examples

socket_stream enables you to communicate with stream socket using C++ iostream.

// Example 1: Simple HTTP client
#include <iostream>
#include <gimite/socket.h>

int main()
{
  // Call this before using any classes in this library.
  gimite::startup_socket();
  {
    // Connects to host www.google.com port 80 (HTTP).
    gimite::socket_stream sst("www.google.com", 80);
    // Checks connection error.
    if (!sst){
      std::cerr << "Failed to connect." << std::endl;
    }else{
      // Sends string.
      sst << "GET / HTTP/1.0\r\n\r\n";
      std::string s;
      // Receives each line and shows it.
      while (std::getline(sst, s))
        std::cout << s << std::endl;
    }
  }
  // Call this after all use of this library has finished.
  gimite::cleanup_socket();
  return 0;
}

server_stream_socket is a wrapper of server side stream socket.

// Example 2: Echo server
#include <iostream>
#include <gimite/socket.h>
 
int main()
{
  // Call this before using any classes in this library.
  gimite::startup_socket();
  {
    // Starts listening to client connection at port 12345.
    gimite::server_stream_socket server(12345);
    // Checks binding error.
    if (!server){
      std::cerr << "Failed to bind socket." << std::endl;
    }else{
      while (true){
        // Waits for client connection, and returns socket handle for connection with first client.
        gimite::socket_t s= server.accept();
        // Creates socket_stream for communication with the client.
        gimite::socket_stream sst(s);
        // Just echoes back string received.
        char c;
        while (sst.get(c))
          sst << c;
      }
    }
  }
  // Call this after all use of this library has finished.
  gimite::cleanup_socket();
  return 0;
}

datagram_socket wraps datagram socket.

// Example 3: UDP communication (server side)
#include <iostream>
#include <gimite/socket.h>
 
int main()
{
   // Call this before using any classes in this library.
  gimite::startup_socket();
  {
    gimite::socket_address saddr;
    // Creates socket at port 12345.
    gimite::datagram_socket dsock(12345);
    char cs[5];
    while (true){
      // Receives 5 bytes packet. saddr points to sender address.
      dsock.recvfrom(cs, 5, &saddr);
      // Shows received string.
      std::cout << "Message from client: " << cs << std::endl;
      // Sends reply packet "pong\0".
      dsock.sendto("pong", 5, &saddr);
    }
  }
  // Call this after all use of this library has finished.
  gimite::cleanup_socket();
  return 0;
}

// Example 4： UDP connection (client side)
#include <iostream>
#include <gimite/socket.h>
 
int main()
{
   // Call this before using any classes in this library.
  gimite::startup_socket();
  {
    // Target is host localhost port 12345.
    gimite::socket_address saddr("localhost", 12345);
    // Creates socket. Port number is automatically allocated.
    gimite::datagram_socket dsock(0);
    // Sends packet "ping\0".
    dsock.sendto("ping", 5, &saddr);
    char cs[5];
    // Receives 5 bytes packet.
    dsock.recvfrom(cs, 5);
    // Shows received string.
　　std::cout << "Message from server: " << cs << std::endl;
　}
　// Call this after all use of this library has finished.
　gimite::cleanup_socket();
　return 0;
}

Global functions

bool startup_socket(); ★★

• Initializes socket system. Call this at first.
• Returns true if it succeed, or false otherwise.
• If you call startup_socket() twice, call cleanup_socket() twice.

void cleanup_socket(); ★★

• Cleans up socket system. Call this at the end.

socket_stream

Wrapper of stream (TCP) socket. It inherits std::iostream. Use normal input/output method of std::iostream to send/receive data.

socket_stream(); ★

• Does nothing.
• Call open() to connect.

socket_stream(const ip_address& host, int port); ★★

• Connects to server.
• host is name or IP address of the server. port is port number of the server.

explicit socket_stream(socket_t sock);

• Creates socket_stream which wraps existing socket handle (e.g. return vaue of ::socket()).
• Note that this socket handle will be automatically closed when the socket_stream is destructed. Use release() to avoid this.

virtual ~socket_stream();

• Disconnects from server.

void open(const ip_address& host, int port); ★

• Connects to server.
• host is name or IP address of the server. port is port number of the server.

void close();

• Disconnects from server.
• Call close() from another thread to finish blocking state of waiting received data.^*1

socket_t release();

• Release socket handle without closing it.

int send(const void* buffer, int size);

• Reads size bytes from buffer and sends them.
• Same as ostream::write().
• Returns sent bytes, or -1 if error.

int recv(void* buffer, int size);

• Receives at most size bytes and writes them to buffer.
• It doesn't wait for receiving size bytes, if it has received at least one byte. This is difference from istream::read().
• Returns received bytes, or -1 if error.

socket_t socket()const;

• Returns socket handle.

operator void*()const; ★
bool operator!()const; ★

• socket_stream is evaluated as true in boolean context (e.g. in IF statement) if it is connected.

*1　I'm not sure this is safe way because socket_stream doesn't care about thread safety :)

server_stream_socket

Wrapper of server side stream (TCP) socket.

server_stream_socket(); ★

• Does nothing.
• Call bind() to bind.

explicit server_stream_socket(int port, int backlog= 5); ★★

• Creates socket and binds it to the port.
• port is the port number. backlog is the size of a queue for connection request.

server_stream_socket(socket_t sock, bool is_bound);

• Creates server_stream socket which wraps an existing socket handle.
• Specify whether the socket is bound or not with is_bound.

~server_stream_socket();

• Closes socket.

bool bind(int port, int backlog= 5); ★

• Creates socket and binds it to the port.
• port is the port number. backlog is the size of a queue for connection request.
• Returns true if it succeeds, or false otherwise. If it fails, you can try to bind to another port.

socket_t accept(); ★★

• Accepts one client connection.
• Returns socket handle (i.e. return value of ::accept()).

void close();

• Closes socket.

socket_t release();

• Release socket handle without closing it.

void socket(socket_t sock, bool is_bound);

• Assigns an existing socket handle to this server_stream_socket.
• Specify whether the socket is bound or not with is_bound.

socket_t socket()const;

• Returns socket handle.

operator const void*()const; ★
bool operator!()const; ★

• socket_stream is evaluated as true in boolean context (e.g. in IF statement) if it is bound.

datagram_socket

Wrapper of datagram (UDP) socket.

datagram_socket(); ★

• Does nothing.
• Call bind() to bind.

explicit datagram_socket(int port); ★★

• Creates socket and bind it to the port.
• port is the port number. Specify 0 to assign automatically.

datagram_socket(socket_t sock, bool is_bound);

• Creates datagram_socket which wraps an existing socket handle.
• Specify whether the socket is bound or not with is_bound.

~datagram_socket();

• Closes socket.

bool bind(int port); ★

• Creates socket and bind it to the port.
• port is the port number. Specify 0 to assign automatically.
• Returns true if it succeeds, or false otherwise. If it fails, you can try to bind to another port.

int recvfrom(void* buffer, int size, socket_address* addr= 0, int flags= 0); ★★

• Receives a packet.
• It writes the packet to buffer.
• size is the number of bytes of the packet.
• It writes sender's address to *addr if addr is not null.
• flags are optional flags which are passed to ::recvfrom().

int sendto(const void* buffer, int size, const socket_address* addr, int flags= 0); ★★

• Sends a packet.
• Sends size bytes from buffer to *addr.
• flags are optional flags which are passed to ::sendto().

void close();

• Closes socket.

socket_t release();

• Releases socket handle without closing it.

void socket(socket_t sock, bool is_bound);

• Assigns an existing socket handle to this server_stream_socket.
• Specify whether the socket is bound or not with is_bound.

socket_t socket()const;

• Returns socket handle.

operator const void*()const; ★
bool operator!()const; ★

• socket_stream is evaluated as true in boolean context (e.g. in IF statement) if it is bound.

ip_address

Class which represents IP address. You can pass std::string or char* instead wherever ip_address is required (e.g. constructor of socket_stream).

explicit ip_address(sock_uint32_t addr= INADDR_NONE);

• Specifies IP address with 32-bit integer.

ip_address(const std::string& host); ★
ip_address(const char* host); ★
ip_address& operator=(const std::string& host);
ip_address& operator=(const char* host);

• Specifies host name (e.g. "www.google.com") or IP address separated with dots (e.g. "127.0.0.1").

in_addr addr()const;

• Returns in_addr structure which represents IP address.

sock_uint32_t as_int()const;

• Returns 32-bit integer which represents IP address.

socket_address

Structure which represents a pair of IP address and port number.

explicit socket_address(const ip_address& i= ip_address(), int p= 0); ★

• Specifies IP address and port number.

ip_address ip;

• IP address.

int port;

• Port number.

Typedefs

Type name	Description	Windows	UNIX
socket_t	Type of socket handle.	SOCKET	int
sock_uint32_t	32-bit unsigned integer which represents IP address.	unsigned long	u_int32_t

History

Ver.1.5	2007/4/5	Renamed diagram_socket to datagram_socket.
Ver.1.4	2004/11/3	Added comparision, equality and output to ostream to ip_address and socket_address.
Ver.1.3	2004/9/21	Fixed a bug that receiving '\xff' is interpreted as EOF in some cases.
Ver.1.2	2004/2/15	Added socket_stream::send() and socket_stream::recv().
Ver.1.1	2003/11/28	Renamed server_socket to server_stream_socket and modified API. Added diagram_socket. Introduced ip_address class which replaced std::string in host name parameter. Tuned socket_stream.
Ver.1.0	2003/10/12	Published.

Contacts

Gimite