RE: dPERINTERP/MY_CXT (was: speeding up XS_DBI_dispatch())

On Fri, 10 Feb 2012, Tim Bunce wrote:
> On Fri, Feb 10, 2012 at 03:27:24PM +0000, Dave Mitchell wrote:
> >
> > If anyone knows of a more elegant way to make a function from DBI.xs
> > available to DBD:: code, please let me know!
> 
> I hope to take a proper look in the next day or so.

The "standard" way nowadays seems to be to use ExtUtils::Depends. I'm
not convinced though that it is any more elegant than the method you are
already using.

An example module using ExtUtils::Depends is B::Hooks::OP::Check.

It is important to also list all exported functions in the FUNCLIST
parameter to MakeMaker; otherwise the symbols will not be exported on
AIX and Windows.

Personally I've just added names to FUNCLIST, and then called
dlopen/dlsym or LoadLibrary/GetProcAddress on the embedding side (not
actually another module, but an app hosting a Perl interpreter).

Ideally you should be able to do this with the DynaLoader dl_load_file()
and dl_find_symbol() functions, but I found some claims (in the FFI
module docs) that this has problems on Windows. I don't know what those
problems are, but it looks like dl_load_file() on Windows will return a
handle to the current executable when the requested library cannot be
found. I have no clue why it is doing that.

So, in summary, I think the current approach isn't such a bad solution
at all. :)
Cheers,
-Jan