Re: Reading From A Pipe

[pub <pub inbox hughes net>]

int    pipefd2[2];    /* Read pipe from child */

Glib::RefPtr<Glib::IOChannel> readChannel;


//Instantiate
Playback playback;

// Connect the signal handler
Glib::signal_io().connect(sigc::mem_fun(playback, &Playback::readpipe), pipefd2[r], Glib::IO_IN);

// Create a writeChannel from the file descriptor
writeChannel = Glib::IOChannel::create_from_fd(pipefd1[w]);

// Create a readChannel from the file descriptor
readChannel = Glib::IOChannel::create_from_fd(pipefd2[r]);

app.run(playback);


// Read From Pipe
bool Playback::readpipe(Glib::IOCondition read_condition)
{
    static int linecount;    // Total lines expected
    static int count;    // Count of lines received



    if ((read_condition & Glib::IO_IN) == 0)
    {
        std::cerr << "Exxx: Invalid read response" << std::endl;
    }
    else
    {
        #ifdef GLIBMM_EXCEPTIONS_ENABLED
        readChannel->read_line(readbuffer);
        #else
        std::auto_ptr<Glib::Error> ex;
        readChannel->read_line(readbuffer, ex);
        if(ex.get())
            std::cerr << "Exxx: " << ex->what() << std::endl;
        #endif //GLIBMM_EXCEPTIONS_ENABLED

        /* Append message read from pipe to textbuffer */
        m_msg->insert(m_msg->end(), readbuffer);
    }
    return true;
} //End of readpipe()

On May 11, 2010, José Alburquerque <jaalburquerque cox net> wrote:

On Tue, 2010-05-11 at 18:23 +0000, pub wrote:
>
> I am trying to read a line from a pipe. After several different tests,
> I get the same results.
> The child is a program that sends 8 lines up the pipe to the Gtkmm
> application.
>
> The first line is read and displayed. Only one line!
>
> The second time, 8 more lines are sent up the pipe.
> I get the 7 remaining lines from the first group of lines plus only
> the first line of the second group. 8 lines total.
>
> Then 8 more lines are displayed in the same pattern, 7 from the
> preceeding group and only the first from the new group.
> This pattern continues until the child stops sending.
>
> It seems like the receive end of the pipe does not show that there is
> remaining lines of data.
>
> Can someone help?

What API specifically are you having trouble with?

--
José