[FFmpeg-devel] [PATCH 3/8] build: treat iconv like other autodetected libraries

Nicolas George george at nsup.org
Fri Jul 28 16:04:29 EEST 2017

Le decadi 10 thermidor, an CCXXV, Clement Boesch a écrit :
> Though, --disable-autodetect will disable its auto-detection, be it
> a "system" or a randomly installed library.

Yes, and I think it is a bad idea for iconv.

> Well, being maintained by the base system or through a normal package
> doesn't make much difference since the system can also gets updated with a
> new iconv (major bumped).

No, it cannot. I am not talking about a library, I am talking about the
API. When the iconv API is part of the system, it cannot change its
binary interface, unless the system gets bumped as a whole.

> Here are some exceptions I can think of: libc (well, hard to get around
> this one)

Well, iconv is part of the libc, so that is ok. It should be treated as
such, like getaddrinfo, i.e. in the SYSTEM_FUNCS list.

>	    and pthread. AFAIK the later may be replaced by "native" code; I
> think clang doesn't rely on a library for this, so I'm assuming there is
> no such thing as a link to libpthread in the final program.

I am rather dubious about that. It is not possible to make real threads
without system calls, and inlining system calls would be very very bad.

> So, unless iconv is a native feature XXXXXXXXXXXXXXX causing the final
> program not to link against any external library

It is exactly that on real Unix systems.


  Nicolas George
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