[Ffmpeg-devel] [RFC] dlopen vs linking for external libraries

Måns Rullgård mans
Fri Feb 16 15:26:07 CET 2007

kabi said:
> 2007/2/14, Uoti Urpala <uoti.urpala at pp1.inet.fi>:
>> On Tue, 2007-02-13 at 15:12 +0100, Luca Barbato wrote:
>> > I don't know the other distribution or the other people, usually you
>> > check the configure script and the readme to write the deplist, not just
>> > random usage of ldd...
>> The default for Debian is to generate (binary) shared library
>> dependencies based on what the binaries actually link to. If you're only
>> familiar with source package build dependencies from Gentoo then those
>> are created by hand.
>> Generating the dependencies automatically allows updating "libfoo-devel"
>> packages as long as the API stays backwards-compatible even if the ABI
>> changes. When you rebuild the application source package with the
>> updated libfoo-devel the resulting binary package will automatically
>> depend on the correct library version; hardcoded library dependencies
>> would fail.
> As a debian maintainer  -

I am sick and tired of debian maintainers acting as if debian were the
undisputed center of the universe, around which everything else revolves,
the maintainers being treated as some sort of prophets.

> I  was the one who added dlopen support to
> ffmpeg - mainly because of legaltity reasons

Give me a break.  There is NO real difference between the system dynamic
linker doing putting the pieces together for you, or the app doing it
manually with dlopen/dlsym.  Sure there are slight technical differences,
and there are reasons one might choose one way over the other, but legal
issues should not be among them.

The debian people need to step down from their high horses for a while, and
see what the ground really looks like.  They might be in for a surprise.

> you can't really distrubute
> mp3 & ac3 decoding libraries and refuse to pay $10000 to some idiots
> who thinks they deserve this money.

People are doing it, and it seems to be doing them no harm.

> The second reason is also the crazy dependency list.

That's why I don't use binary distributions.  You simply can't both eat
the cake and keep it.

> So for me - I prefer that each externaly used library support boht methods
> (and as can be seen in a52 or faad library - it easy to do & maintain
> and doesn't slow anything)

It *does* require more development effort.  There's no denying that.

M?ns Rullg?rd
mans at mansr.com

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