Libevent is pretty cool, but it is not “fast” for all applications. For example, it retrieves the system clock frequently, which can be a performance. libtorque: Portable Multithreaded Continuations decade’s architectures and operating systems, as libevent [19], libev, Java NIO and others achieved ubiquity much room for improving non-blocking I/O solu- Network programming abounds with task idioms. .. this approach could be the fastest path to true zero- . I want to know how to use libevent l.4,especially the use of http. can anybody give me a Fast portable non-blocking network programming with Libevent.

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Wait for the connection to become writable Write as much of the data as we can Remember how much we wrote, and if we still have more data to write, wait for the connection to become writable again.

Equals to NULLif there is no file descriptor socket associated with the buffer event. It seems that a lot of people sincerely believe that this stuff is “easier” or “better” just because it has the fancy new Spicy Event Sauce. But it’s a tradeoff: Edit Report a Bug.

The short answer may very well be no, since it somewhat depends on the programming language one chooses to use. Once you portsble up a non-blocking event loop, it’s much simpler when you can go async all the way down.

Also, the maintainer only updates sporadically, but I’ve never had real problems with it.

Fast portable non-blocking network programming with Libevent | Hacker News

But it’s difficult and error-prone. An error occurred during a bufferevent operation. Event-based code obscures control flow, as you note; threaded code is subject to very subtle and noon bugs. It wasn’t too long ago when people were excited about fork-for-each-connection servers, though at least half of it was “OMG Unix system calls from Ruby” from people who probably don’t know C.


EOF Got an end-of-file indication on the buffer event. Normally represents a bound socket. This will close an underlying socket, free an underlying buffer event, etc. If I had to speculate: Wwith is rock solid — it handles the event loop for memcache, among other things.

Fawt, some observations on server design from Jeff Darcy http: Thanks to you and ajross, this really helps.

It feels sort of like writing in continuation-passing-style. Note that gevent is a fork of Eventlet http: When the buffer event is freed, close the underlying transport. Numeric file descriptor associated with the buffer event. An event occured during a write operation on the bufferevent. That means you’ll often be stuck with limited capabilties, unless you write your own libraries or hack up existing ones.

We do a lot of network programming, so it would be unthinkable for any performance intensive application to do blocking calls exclusively. It’s frombut is wkth good overview of well-understood techniques. This is hardly a new idea, in fact it’s very well-traveled ground. It splits sequential algorithms up into multiple callbacks with manually managed shared state.

UNIX for Advanced & Expert Users

Simpler approaches are good enough sometimes, though. One problem with using an event dispatcher like libevent is that libraries that make their own blocking calls won’t cooperate. It uses greenlets to make code written sychronously run asynchronously behind the scenes. When this flag is set, the bufferevent defers all of its callbacks.


What exactly is it that made this thing the snake oil of the week? It isn’t snake oil – it nom and works well in the right situations. It’s one of those things that I’ve read about different methods here and there, but I’ve never come across one good source that compared and contrasted the various techniques.

If you run a single thread without the event based approacheach request must wait for preceding requests to finish entirely before running. Event programming is useful in that it effectively performs cooperative multitasking without the overhead of thread stack space. It makes “what happens next” a really hard problem. Again, event stuff has been here forever, and clearly is appropriate noon some tasks.

But most apps don’t fall into those categories, and I’m not getting any of that vibe from this. There’s a Python project called gevent http: Fast portable non-blocking network programming with Libevent wangafu.

Constructing signal events

For more information on what the error was, call EventUtil:: Multiple requests can be running in parallel without fully blocking each other.

I have used it to much success — some people don’t like the minimalist style. Underlying output buffer object EventBuffer.