[FFmpeg-devel] OpenCV filter should be built as C++, and C builds fail since OpenCV 3.4.1

Tobias Rapp t.rapp at noa-archive.com
Tue Mar 20 17:28:54 EET 2018

On 20.03.2018 16:02, Nicolas George wrote:
> Derek Buitenhuis (2018-03-19):
>> If you want to link with a C++ library that is indeed the 'proper' solution.
>> As far as I am aware "several languages all have that requirement" is simply
>> a theoretical scenario that doesn't actually exist. What else beside C++
>> requires this?
> No, it is not a theoretical scenario: most languages that produce native
> code have the requirement to produce the final binary using their
> toolchain. It is true for OCaml: you need to use ocamlopt to produce a
> binary, even if using a third-party C library; I believe it is true for
> Rust too.

Not really. You can compile parts of a program in Rust (as a static 
library) and link it to other parts in C producing the final binary with 
e.g gcc.

> The problem happens when you want to mix several of these languages,
> because the requirements are incompatible.
> Fortunately, most people who program in other languages than C are not
> stupid enough to use them to produce libraries, except for use with that
> language itself. Except c++ people, for some reason.

If the libraries don't depend on some run-time environment and provide a 
C-compatible ABI, mixing languages (like C, Delphi, Rust) is not a problem.


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