I'm looking for suggestions about choosing a portable way to achieve local IPC in a robust way, since i'm new to C++ and would like to avoid common pitfalls of fiddling with shared memory and locks; therefore I was thinking about message-passing style ipc.
I was planning to use qt for other reasons anyway, thus i took a peek to Qt ipc options.
if i understand correctly qt doesn't offer a completely portable message-passing ipc feature. it can use d-bus, but using it on windows would be a problem. other ways are limited to embedded linux platforms (and i would like to port this thing to AIX).
I could not find a "signal and slots" or message-passing style implementation that uses QSharedMemory and QSystemSemaphores
Thus: Am I limited to implement a feature on QSM/QSS?
what other options could i study?
posix pipes? protocol buffers? boost queues and messages ?
I'm considering to release the code under LGPL/GPL style license, does this rule out protocol buffers or boost libs?
please, again, the interface must be simple and newbie-proof (otherwise i definitely will screw up things big time for sure :) ), and so should the serialization/deserialization of types, error handling and resource disposal.
Take a look at Boost.Interprocess which provides a lot of IPC functionality. I have used the interprocess message_queue that provides a pretty clean and easy way to do what I think you want to do.
You can use QLocalSocket and QlocalServer for IPC too.
Those two classes are really easy to use and they can be implemented ~almost the same way as you would using Qt TCP socket client/server.
You can take a look at some of these youtube videos:
QTCPServer - a basic TCP server application
QTcpServer using multiple threads
(Almost the sames principles would apply for "Local" server/client instead of "TCP")
As Qt 5.9, there is module which is currently under technology preview name QtRemoteObjects which provides Qt native IPC for QObjects, its easy to use and could be used to share signal/slots and also models between two processes.
Its works well for Linux, Windows and android
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I am looking to write a server application in C++ that is meant to handle tens of thousands of clients simultaneously. It should run under Windows and Linux. I have been looking around for frameworks and libraries and have come across Boost Asio, which seems like a highly mature and widely used alternative. I just have trouble wrapping my head around strands/thread pools, mainly because of the millions of templates. My background is mainly in C, so am not really used to the template mess that Boost in general seems to be full of. I tried to find someone to develop a relatively thin wrapper around Boost Asio that would take care of the threading/synchronization aspect using strands, bind and the like, but have been unable to find someone yet who can do it within my budget (2 or 300 US dollars).
Can any of you recommend any other libraries that scale as well as Boost Asio (e.g. with IOCP on Windows and epoll on Linux etc), or a source where I might find skilled Boost developers looking for smaller freelance jobs?
Thanks very much in advance for any help.
Kind regards,
Philip Bennefall
Best 4 choices i know
I really like zeromq.. but libuv seems interesting.. (libev and libevent are very nice too)
zeromq
libevent (as said)
libev
libuv (Its purpose is to abstract
IOCP on windows and libev on Unix systems and it is node.js network layer)
ACE is the framework you are looking for. Even boost Asio is just an implementation of Proactor pattern, which was introduced by Douglas C. Schmidt. He is best known as the author of POSA Vol.2 and the creator of ACE framework.
The Boost.Asio library offers side-by-side support for synchronous
and asynchronous operations ... based on the Proactor design pattern
[POSA2].
Although it is a cross-platform C++ network framework and uses template,
just simple template is used. (or not at all)
My background is mainly in C, too, and I don't like Boost's massive template-programming style. However, ACE wasn't like that.
Try libevent on for size. Its whole raison d'etre is to address the C10K problem. I'd say it's probably more lightweight than boost.
Try Pulsar Server Framework. Main benefit is it is built over libuv network library (used by node.js) that uses asynchronous I/O based on event loops.
It’s perfectly scalable. You can just go adding servers as your user base increases.
It is designed to work with server farm.
Highly configurable and easy to use
Currently it has been built for Windows x64 server.
I really thought this would be easier to find...
I need a portable c++ sockets wrapper. I'm planning to use it for a windows server application and a client that will be running on a embedded device running ulinux (or something similar). I would use Boost but I need it to be lightweight and easy to add to the embedded device project.
Also I would like it to be a "higher level" wrapper... so it starts a background thread to read data and informs be over a callback...
Any ideas?
I'd suggest Boost.Asio. Despite it's name, you are not forced to use asynchronous I/O. You could use synchronous I/O and threads, as your question implies.
Boost.Asio is a cross-platform C++
library for network and low-level I/O
programming that provides developers
with a consistent asynchronous model
using a modern C++ approach.
Just learn to use the socket API directly. You can then easily wrap it yourself. It's not that hard, and you can get started with Beej's excellent guide. As Beej says:
The sockets API, though started by the
Berkeley folk, has been ported to many
many platforms, including Unix, Linux,
and even Windows.
In his guide he details the very small addition you need to do to get the same API in Windows and *nix systems.
Once you've learned, wrap it yourself if you're so inclined. Then you can control exactly how "lightweight" you want it.
If you really don't like Boost asio then you might like the sockets support in dlib. It is simpler in the sense that it uses traditional blocking IO and threads rather than asio's asynchronous proactor pattern. For example, it makes it easy to make a threaded TCP server that reads and writes from the iostreams. See this example for instance. Or you can just make a simple iosockstream if not acting as a server.
I know this is old, but there is a very nice and simple implementation in below location which I'm using for personal use. Had implemented my own wrapper a while back but lost the code and found this one online which is much better than mine:
http://cs.ecs.baylor.edu/~donahoo/practical/CSockets/practical/
Take a look at ENet http://enet.bespin.org/ it is very lightweight and portable and works on top of UDP, with optional support for reliable packets. It is easy to use, the API is low-level and with little performance overhead. You have a high degree of control over the memory management, which could be good if networking is a bottleneck for you and the malloc/new implementation you use performs badly under multithreading.
It would not be that hard to implement your high level thread “optimally”, since there is optional support for blocking receive and the library is a “library” and not a framework therefore you are the decision maker instead of the library.
Perhaps you can have a look at http://www.pt-framework.org/
Old question, but for C++, BSD style synchronous sockets this is about as minimal baggage wrapper as you can find
http://code.google.com/p/ting/source/browse/trunk/src/ting/net/
It does come with exceptions. You could make a bit more lightweight one as a header-only template library, and maybe make exceptions optional, but that would change the API a bit
POCO network classes are quite similar, but do require more dependencies from other parts of the Poco lib
I'm personally creating my own AsIO wrapper for both TCP and Serial sockets, and I started by reviewing the following tutorial:
https://www.gamedev.net/blogs/blog/950-they-dont-teach-this-stuff-in-school/
and
https://objectcomputing.com/resources/publications/mnb/multi-platform-serial-interfacing-using-boost-a-gps-sensor-and-opendds-part-i/
I found the first one very useful and simple to understand.
C++CSP2
Used it loved it. Stable and powerful
I'm trying to implement my own IRC client as a personal proejct and I realized I needed a way to read and write from the socket at the same time. I realized I could have a reading thread which reads from the socket in the background and puts data in a queue and I could have another thread which writes data from a queue to the socket. However I have no idea on how to start with multithreaded programing or how to do it with c++. Where do I go from here?
For C++ threads, boost::thread (which is the basis for the upcoming std::thread) is the best way to go. That said, while threads might be the correct solution for your particular case, I just wanted to throw it out there that select and non-blocking sockets are a common approach to interleaving the reading/writing and writing of multiple sockets without the need for threads. The boost::asio library wraps the functionality of select and non-blocking sockets in a cross-platform, C++ manner.
It's specific to C and *nix, but I can't think of a better starting place than Beej's Guide to Network Programming. "You will learn from the Jedi Master who instructed me."
You'll learn the basics of reading and writing to sockets, and more importantly, that multi-threading isn't necessarily the right answer.
I would suggest using Qt Threading. It is highly documented with really excellent sample code on almost every feature. Plus they are LGPL licensed now and will run on most every platform and include the source code with the binaries. They also have very good network supoort.
Whatever way you choose, make sure that they have good documentation and samples
I'd suggest looking at the POCO libraries. In my opinion they are easier to get on with than boost and have excellent documentation. These libs provide great frameworks for writing multithreaded networking code. You can learn a lot from them and get up and running pretty quickly.
I suggest ACE. It has portable abstractions for many operating system functions (*nix, Windows etc): BSD sockets, Threads, Mutexes, Semaphores etc - write once compile anywhere (See ACE_OS namespace of ACE).
It has a lot of network application patterns you can use (ACE_Reactor would be good for the beginning) but you can use the portable abstractions of the BSD functions (socket, send, recv, close, select - they are enough for your IRC client)
As previously mentioned boost is also an option and usually any cross-platform library providing portable abstractions for each operating system (I can think of wxWidgets, qt for the graphical part - if you want to do this).
And one advice: do not use threads unless you really need to. They are not as easy as it seems.
When referring to the network communication I believe that what you want to do is easily achievable in a single threaded application(ACE_Reactor helps you a lot here but you are free to use the BSD socket functions). First understand how sockets work, then - if you want to - understand how the reactor makes use of sockets in its network application patterns(ACE_Reactor works in conjuction with ACE_Event_Handler objects).
Hope it helps!
I wonder what library would ease the development of a cross-platform service/daemon ? (C/C++)
I'm targeting: Windows, Linux and OS X.
Requirements: network operations and serial port communication.
Also it would be nice to have a basic sample service application.
When it comes to Qt you might try qt-service.
A daemon in Linux is really just a process that runs disconnected from a terminal. In Windows, a service is something that can be controlled using the service management API, but once again is basically just a disconnected process. The disconnection aside, daemons & servers don't have much in common, from task to task. There is no requirement, for example, that they be multi-threaded, be asynchronous or perform network I/O. Given that, it's kind of hard to see what a cross-platform library would do.
You should take a look POCO. Depending on what you are doing it could have facilities to do a large amount of the work for you with a lot less work than Boost.
An obligatory mention for ACE though I don't personally care for it much.
Boost probably has most of what you need in terms of threading and networking I/O.
You may also find Qt a good alternative. It also has threading and networking libraries and has a much easier to use & understand event-driven programming model using a run loop. Qt's signal/slot system is very easy to use and ideal for a network daemon/service (Boost also includes a signal/slot system but it is harder to use and does not include an event loop; you have to roll your own using some event library). As a cross-platform library, Qt can handle many of the issues in bridging the Unix (OS X and Linux) vs. Windows mental model for processes, filesystems, etc.
For unit testing, I've been very happy with Google's C++ unit testing library called googletest (though both Boost and Qt also have built-in unit testing systems). It runs on all the platforms you specify. I've done a lot of work with googletest on cross-platform Qt projects and found it quite satisfactory.
I've found a big library in the non-boost version of ASIO. You don't need all boost library but only this little headers-only and very well documented library http://think-async.com/
As examples, a daytime server-client system is implemented in very few lines of code.
Take a look at it.
(remember to look at the non boost-ized version)
Things to take into consideration:
- easy to use
- fast
- use underlying OS as much as feasable (like wxWidgets for UI)
Ones I am leaning towards are wxWidgets for UI and Boost for networking - how do they compare to others?
I hear good things about qt for GUI
Qt is a cross-platform application and
UI framework. Using Qt, you can write
web-enabled applications once and
deploy them across desktop, mobile and
embedded operating systems without
rewriting the source code
I've had good look with wxWidgets on the front end and boost::asio on the network end.
wxWidgets does have network classes built in, but you hit the wall quickly on them, and there's one or two big limitations. If you want to stay in the wx world, there's a package called wxCurl which is a fine package (I used it in the early days) that wraps libCurl with some wxWidgets idomatic C++.
In a previous project of mine (a network/file transfer heavy project) we ended up going with boost::asio, which had the advantage of not being all that hard of an API, easier-seeming to set up that libCRUL (although that may have gotten better, that was been several years now), and gives us a very generic networking core (boost can compile anywhere, even command line apps)
For GUI I would strongly recommend using Qt. It is very powerful GUI framework that requires writing very few lines of code. It has very nice and easy to use model of signals and slots.
wxWidgets IMHO too modeled after MFC which has very bad model.
Networking: I would suggest go for Boost.Asio very powerful and nice. However if you
want to integrate networking to GUI main loop you may try to use Qt classes for that, however I have no experience with them.
I've used XVT historically, which has been used commercially by thousands of companies.
Both Qt or wxWidgets can do networking even if it's not their first goal.
For more network centric libraries, apart from boost::asio, you can check ACE (Adaptative Communication
Environment ) or POCO
Comparisons between these libraries have already been discussed on stackoverflow.
boost::asio seems to be very well written, and has a very clean API -- I am still trying to learn how well it is for shared-nothing multithreaded TCP/IP.
Your other choices might be Poco, or ACE. Poco's socket abstraction is quite naive --i.e., it only allows the Poco way of doing things. I've never heard anything good about ACE.
edit: Hmm, I'm re-examining ACE and its making more sense to me now (after having written a few networking apps) -- it might be suitable for my needs compared to ASIO. However, it is more than likely overkill for you. If my peers find out about this, I will be shunned till the end of time.
We have had good success using wxWidgets with boost::asio, both recommended for desktop-server development.
For GUI, I can recommend QT
For Networking ACE (Adaptive Communication Environment) or boost::asio.