Re: [asio-users] A strange issue on Linux, but on Windows works perfectly

[Dmitry T. <dim...@gm...>]

Hello, again

I told about the strange issue, I also told it happens only for 
async_connect... I've little bit mistaken.

The new assertion is:
there is no difference how the connection is initiated. It may be client 
(async_connect) or server (async_accept)
the issue occurs anyway. Accept and connect handlers are invoked, but 
read and write handlers are NOT.
This means they are never called from within io_service::poll()
I didn't check io_service::run() and etc. I only checked io_service::poll().

I spent a lot of time to make this clear and this is what I found out.

I use asio in one of common ways. There is only one thread everything is 
called from within.
io_service::poll() is permanently called, after it finishes the main 
process() function is called doing all the work to handle incoming
data and put outgoing data into the out queue by calling async_read() & 
async_write()
(I tried different variants provided by asio: async_read_some and etc.).

The code looks like this in simple way.

void main_loop(void)
{
    while (is_working())
    {
      _io_service.poll();
      process();
    }
}

void handle_accept()
{
    // first call to async_read()
    start_read();
}

This pefectly works on Windows, but on Linux I get handlers specified to 
async_read() & async_write() are not actually called
even if data (incoming or outgoing) exist (I strictly checked this).
There only accept handler is called on server side. io_service is just 
silent.
Acceptor is also works wrong. In my case I only serve one connection, so 
when the connection is accepted I close the listening socket.
When the connection is broken I reopen it. But it's not opened again! It 
only can be opened if I restart the program.

There is a solution:
If boost::asio::io_service::work is used everything works as should have 
been under both Windows and Linux.
I create work object before start main_loop() and destroy after 
main_loop() exits.
After I did it, the issue disappeared. asio::acceptor also works properly.

If you need test project, or something else, please tell me.
Thank you.