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C++ Socket library tutorial

Standard input

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When reading user input from the console, in a singlethreaded environment one can't just stay somewhere in the program and wait. That would halt all execution of other parts of the program.

The Stdin class attaches to file descriptor STDIN_FILENO (0). When added to a SocketHandler, read events from stdin will cause OnRead on Stdin to be called. Using read(), characters typed at the console can be retrieved. Finally, OnData is called with a buffer pointer to the chars just read, and the length. OnData is the method that Stdin derived classes must implement to read console input.

The Stdin class is used in example 10 - the ICMP chat.

Stdin.h
/**
 **	File ......... Stdin.h
 **	Published ....  2004-07-03
 **	Author ....... grymse@alhem.net
**/
/*
Copyright (C) 2004  Anders Hedstrom
Parts Copyright (c) Vergil of Ragestorm.net, 2003

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
#ifndef _STDIN_H
#define _STDIN_H

#include "Socket.h"


class Stdin : public Socket
{
public:
	Stdin(ISocketHandler&,size_t bufsize = 1000);

	/** characters from stdin, including crlf's */
	virtual void OnData(const char *,size_t) = 0;

protected:
	void OnRead();

private:
	size_t m_bufsize;
};


#endif // _STDIN_H

Stdin.cpp
/**
 **	File ......... Stdin.cpp
 **	Published ....  2004-07-03
 **	Author ....... grymse@alhem.net
**/
/*
Copyright (C) 2004  Anders Hedstrom
Parts Copyright (c) Vergil of Ragestorm.net, 2003

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
#include <errno.h>
#include "ISocketHandler.h"
#include "Stdin.h"


Stdin::Stdin(ISocketHandler& h,size_t bufsize) : Socket(h)
,m_bufsize(bufsize)
{
	Attach( STDIN_FILENO );
	Handler().ISocketHandler_Add(this, true, false);
}


void Stdin::OnRead()
{
	char buf[m_bufsize];
	int n = read(GetSocket(), buf, m_bufsize + 1); //recv(0, buf, 1000, 0);
	if (n == -1)
	{
		Handler().LogError(this, "OnRead", errno, strerror(errno), LOG_LEVEL_FATAL);
		SetCloseAndDelete();
		return;
	}
	OnData(buf, n);
}



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