Re: [Boost-users] [ASIO] Synchronous write on serial_port

Subject: Re: [Boost-users] [ASIO] Synchronous write on serial_port
From: Daniele Barzotti (daniele.barzotti_at_[hidden])
Date: 2009-04-07 11:55:55

Hi,

I've isolated the problem (I think). But I can't understand why it works
in this manner!!

I've posted a working code in attach (made with VS2008 EXP), if someone
could give me some feedback I will grate to him!

In the code there are two wrapper classes for the asio::serial_port, one
that works well and the other (mine) that has the issue!

Thanks in advance.
Daniele.

Daniele Barzotti wrote:
> Hi,
> 
> I'm developing a library that use ASIO Serial Port and I need to
> implement a synchronous write.
> 
> The structure is:
> 
> EuroATLib.cpp    : library main file
> Serial.cpp       : serial port class that wrap asio::serial_port
> ATDispatcher.cpp : a dispatcher object
> ATModem.cpp      : the consumer object
> 
> The problem is that my code writes characters on serial port very slowly
> (1 char every 10 seconds) and I can't understand why.
> Also, when the program ends, the io_service thread seems to be already
> alive: it continues to write to serial port for a while!
> 
> The implementation is like this...can someone give me some feedback?
> 
> PS: In the following code TBUFFER is std:string.
> 
> 
> In EuroATLib.cpp :
> ----------------------------------------------------------
> // Main io_service
> static boost::asio::io_service          io_service;
> static boost::scoped_ptr<boost::thread> io_service_thread;
> 
> /*!
>   \brief Factory function for ATModem objects creation
> */
> EXTERN_C EUROATLIB_API ATModem* CALL CreateATModemObj()
> {
>   static bool thread_started;
>   if (!thread_started) {
>     try {
>       // run the IO service as a separate thread
>       io_service_thread.reset(new boost::thread(
> boost::bind(&boost::asio::io_service::run, &io_service) ));
>       thread_started = !thread_started;
>     } catch (boost::thread_resource_error e) {
>       // Failed to create the new thread
>       return 0;
>     }
>   }
>   // create the new object
>   return new ATModem(io_service);
> };
> ----------------------------------------------------------
> 
> In Serial.hpp :
> ----------------------------------------------------------
> // the main IO service that runs this connection
> boost::asio::io_service& _io_service;
> // the serial port this instance is connected to
> boost::asio::serial_port _serialPort;
> ----------------------------------------------------------
> 
> In Serial.cpp :
> ----------------------------------------------------------
> 
> SerialPort::SerialPort(boost::asio::io_service &_io) :
>                        m_buffer_size(100),
>                        _io_service(_io),
>                        _serialPort(_io_service),
>                        _rx_timer(_io_service),
>                        ReadTimeOut(READ_TIMEOUT)
> {
>   //init_dcs();
>   EosString = '\n';
>   _buf = 0;
> };
> 
> BOOL SerialPort::Write(TBUFFER &buffer)
> {
>   _io_service.post(boost::bind(&SerialPort::do_write, this, buffer));
>   return true;
> };
> 
> void SerialPort::do_write(TBUFFER &buffer)
> {
>   // size_t byte_written = boost::asio::write(_serialPort,
> boost::asio::buffer(buffer.c_str(), buffer.size()));
>   size_t byte_written =
> _serialPort.write_some(boost::asio::buffer(buffer.c_str(),
> buffer.size()));
> };
> 
> ----------------------------------------------------------
> 
> In ATDispatcher.cpp simply have a SerialPort member and a function
> SendCommand that start a timer and call Serial.Write(cmd)
> 
> In ATModem.cpp I have an ATDispatcher Object on which it calls
> disp_obj.SendCommand("AT+CMGS"):
> 
> ----------------------------------------------------------
> RET_VAL ATModem::Connect(std::string DevName)
> {
>   if (DevName.length() > 0) SetComPort(DevName);
>   if (!_serial_port.Open()) return -1;
> 
>   //Connect the OnDataReceived event to the ATDispatcher object
>   _dispatcher->OnData(boost::bind(&EuroATLib::ATModem::OnDataReceived,
> this));
> 
>   //Register Voice Service
>   if ( _dispatcher->SendCommand("AT+CTSP=2,0,0") != ATDispatcher::RET_OK
> ) return DEV_AT_CMD_ERROR;
>   //Register STATUS Service
>   if ( _dispatcher->SendCommand("AT+CTSP=2,2,20") !=
> ATDispatcher::RET_OK ) return DEV_AT_CMD_ERROR;
> 
>   this->SetStatus(STATE_READY);
> };
> ----------------------------------------------------------
> 
> Finally in the main client program:
> 
>   // Create a ATModem object
>   boost::scoped_ptr<ATModem> _devATModem( CreateATModemObj() );
>   _devATModem->Connect("\\\\.\\COM1");
> 
> 
>