The language itself has no I/O at all. Even setTimeout and setInterval are implemented by the libuv bindings using uv_timer_t instances. In the browser the language VM is bound to the browser natives and APIs. In node, the language is bound to libuv and other natives that node exposes.
As far as callbacks, *every* true event source must come from C somewhere. JavaScript cannot create new event sources on it's own. You can create a function that wraps an async source (like the uv_timer_t interface) and exposes a different API in javascript (like setTimeout). In node, there are bindings providing all the I/O (timers, tcp, pipes, tty, fs, udp, dns, etc) and some C bindings for operations that CPU intensive or hard to implement (http parsing, crypto, compression, etc..) For specifics, here is the C++ <-> JavaScript binding bridge for uv_timer_t https://github.com/joyent/node/blob/master/src/timer_wrap.cc . And here is the JS API wrapper to expose this as the well known setTimeout interface: https://github.com/joyent/node/blob/master/lib/timers.js#L180-L214 Hope this helps, let me know if you have more questions. There is a lot going on here. -Tim Caswell On Mon, Feb 11, 2013 at 8:47 AM, Bodo Kaiser <bodo.kai...@enabre.com> wrote: > Hello, > > last weekend I asked how nodejs event loop worked and I became a great > link about it: http://nikhilm.github.com/uvbook/basics.html#event-loops > > Unfortunately I still got a major understanding problem about nodejs: > When we use some node modules which itself look like plain javascript then > in the background libuv has to handle them somehow (e.g. tcp sockets) but > how could I imagine this? > Does the javascript get parsed by v8 which detects defined classes and > informs libuv to do the tasks the overlaying tcp sockets are configured for? > And what is about some "normal" javascript-language callbacks (e.g. > setTimeout). Are they also handled by v8 or libuv? > > > I think I do not understand what the v8 engine does exactly and how the > other libs are bound into. Could somebody clarify me? > > Regards, > Bodo > > -- > -- > Job Board: http://jobs.nodejs.org/ > Posting guidelines: > https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines > You received this message because you are subscribed to the Google > Groups "nodejs" group. > To post to this group, send email to nodejs@googlegroups.com > To unsubscribe from this group, send email to > nodejs+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/nodejs?hl=en?hl=en > > --- > You received this message because you are subscribed to the Google Groups > "nodejs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to nodejs+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to nodejs@googlegroups.com To unsubscribe from this group, send email to nodejs+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en --- You received this message because you are subscribed to the Google Groups "nodejs" group. To unsubscribe from this group and stop receiving emails from it, send an email to nodejs+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
