How to use matching settings for synchronous and asynchronous pipes

[cyki]

Hello everyone,

I have written client application with Qt using QLocalSocket class. As I know Qt opens asynchronous I/O pipes. What if a server was not written in Qt (so it opened synchronous I/O pipe)? Is it possible to tell my client to connect to synchronous I/O pipe? How to use matching settings in such situations? I can change only client side - I do not have access to the server code which is syslog_ng application. When client tries to connect I obtain error: ConnectionRefusedError.

[cyki]

I am using Linux OS. I have written server application with Qt using QLocalServer class and my client communicates with this server correctly. The problem occures when pipe is open by application that was not written in Qt, e.g. I create named pipe by means of linux command:
$ mkfifo /tmp/test
Then I write some text into this pipe:
$ echo "this is my text" > /tmep/test &
Now I can read this pipe by means of cat application:
$ cat /tmp/test
but when I am trying to read this pipe by means of my client I receive following error: ConnectionRefusedError.
Is it some kind of incompability? Does asynchronous and synchronous I/O pipe concern only Windows or Linux as well?

[anda_skoa]

I have written client application with Qt using QLocalSocket class. As I know Qt opens asynchronous I/O pipes. What if a server was not written in Qt (so it opened synchronous I/O pipe)?

Not a problem, server and clients are independent.

Is it possible to tell my client to connect to synchronous I/O pipe?

A socket is neither sychronous nor asynchronous, it simply is.
Any participant can open it they way it wants to, without any impact on its peer.

I create named pipe by means of linux command:
$ mkfifo /tmp/test

Probaly a misunderstanding, but this is a pipe, not a Unix domain socket.

Cheers,
_

[cyki]

Ok, thanks for the answer!

How to create then an application in Qt that will read pipe created by means of mkfifo command?
I used QLocalSocket class in following way:

localSocket = new QLocalSocket(this)
localSocket->connectToServer(/tmep/test, QIODevice::ReadOnly)

but connectToServer() function returns ConnectionRefusedError.

[anda_skoa]

QLocalSocket uses Unix Domain sockets, not pipes.

You can use system I/O API but very likely also QFile.

Cheers,
_

[cyki]

OK, now it's clear. Thanks for the help