RE: noob luajit library loading on unix question
- From: William Adams <william_a_adams@xxxxxxx>
- To: "luajit@xxxxxxxxxxxxx" <luajit@xxxxxxxxxxxxx>
- Date: Tue, 30 Oct 2012 21:05:05 +0000
Thanks for the pointers on the version specific stuff. I had built libev from
scratch, but no magic incantations.
My plan has been to bypass libev enventually, and go to bare metal, as you
suggest. Libev provides me with a good starting point, although, it's already
in the way.
As far as the types of events, I want to support everything from
mouse/keyboard/timer to sockets, so ultimately, I will do poll as well, but
perhaps as a separable thing.
Looking at libev, I don't expect there to be much difficulty in going straight
to select.
-- William
===============================
- Shaping clay is easier than digging it out of the ground.
> Date: Tue, 30 Oct 2012 16:49:30 +0100
> From: mike-1210@xxxxxxxxxx
> To: luajit@xxxxxxxxxxxxx
> Subject: Re: noob luajit library loading on unix question
>
> William Adams wrote:
> > I've got a ffi interop thing to libev running on Linux
> > (Raspberry Pi). When it comes time to load the library, I seem
> > to have to load it explicitly like this:
> >
> > local libev = ffi.load('libev.so.4.0.0')
>
> Correct would be 'libev.so.4'.
>
> > There is a soft link to the library, named libev.so, and I
> > thought I'd be able to do this:
>
> The symlink is only present if you've installed the libev4-dev
> package. You can't expect it to be always present on users
> systems.
>
> > Is this normal for Linux systems, or am I missing someting?
>
> Nope, that's normal. To *build* a package you need the -dev
> packages of all required libraries. The linker resolves the
> library dependency to the versioned name at build time.
>
> When a package is *installed* (on a different system) it only
> needs the non-dev library packages. It always loads the versioned
> library and doesn't need the non-versioned symlink.
>
> Ok, so that causes problems for the FFI -- but that's how Linux
> distros work. You really need to load the versioned name. Or you
> could try to load different versions (wrap it in pcall) as long as
> the API functions you're using haven't changed.
>
> [BTW: That begs the question why you're adding a dependency to
> libev for a framework that's Linux-specific, anyway? You might as
> well add a small wrapper for poll or epoll and be done. Avoids
> callback hell, too. And don't bother with epoll unless you're
> aiming for high scalability -- poll is much easier to handle and
> good enough for most use cases.]
>
> --Mike
>
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