Where should D programs look for .so files on Linux (by default)?

[H. S. Teoh via Digitalmars-d]

On Wed, Sep 17, 2014 at 04:43:04PM +0000, Dicebot via Digitalmars-d wrote:
> I presume you mean dynamically loaded .so libraries and not just
> dynamically linked? Because latter use the same library path
> resolution rules as in C world (ld takes care of that)
> 
> As for dynamically loaded ones - it is somewhat tough question.
> Loading non-local plugin .so libraries is quite unusual, Derelict is
> the only software I know that does it. I am not sure it is even a good
> idea in general.
> 
> Are there any examples how this is solved in other languages /
> platforms?

In C / Posix, you can load any library dynamically using dlopen(),
dlsym(), et al, manually "link" your program by extracting function
pointers and data pointers. Some applications use this to implement a
plugin mechanism -- some Linux media players do this, I believe, and
browsers probably also use the same mechanism for browser plugins.

In any case, dlopen() uses the OS's dynamic linker to find libraries, so
it's really a matter of setting up your OS environment to be able to
find the libraries. It's not really within the scope of the D runtime to
attempt to configure this. Furthermore, some application plugin
frameworks may do things like fiddle with LD_LIBRARY_PATH to get it to
look for libraries where the dynamic linker wouldn't usually look; in
that case, you're really at the mercy of the plugin framework author(s)
as to how to configure such lookups. Again, it's not really within the D
runtime's mandate to control such things.

As for how it works on Windows, I have no idea at all. It's probably
completely different from Posix, which is more reason to leave it up to
plugin framework implementors to implement, rather than hard-coding an
incomplete / inconsistent implementation in druntime.


T

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