Re: Is it possible/acceptable to create a component in Gambas that depends on a shared library?

[Benoît Minisini <benoit.minisini@xxxxxxxxxxxxxxxx>]

Le 06/02/2026 à 21:16, Lee a écrit :
> The recent thread on reading barcodes prompted me to revisit this idea.
>
> A while back I wrote a project that used "droidcam" and "zbarcam" to 
> read barcodes using a smartphone. It works adequately, but managing each 
> external process to make the user experience less cumbersome is more 
> cumbersome in the code.
>
> It would be nice to be able to manage the reader directly from Gambas. 
> But, it is even acceptable to create a component in Gambas that depends 
> on a shared library?
>
> I see that gb.scanner relies on `scanimage`, but that is a command-line 
> tool the existence of which is easily tested with System.Exist(). Also, 
> I see that gb.openssl relies on the "openssl" library but that component 
> is written in C and appears to statically link with the library.
>
> Is there a "proper" way to do what I am asking including relatively 
> easily testing for the existence of the shared library to raise an error 
> if it does not exist? Or is creating a component in Gambas that relies 
> on a shared library (perhaps highly) discouraged if not prohibited?

It's not a good idea, because library are supposed to be used directly 
only by a compiled language.

The library provides interface files (C or C++ headers) for that, that 
are tested at compilation time through the 'pkg-config' file and version 
requirements or by just checking the availability of these interface 
files on the system, and adapting your code to the interface version.

If the interface library changes, your program usually does not compile 
anymore.

When you package a project using that library, you are supposed to 
create a dependency on the library package, with versions requirements, 
so that the interfaces used by the project at compile time match the 
interfaces provided by the library package at runtime.

How will you do that with a Gambas program at runtime only?

--
Benoît Minisini.