On 2012-08-20 17:16, Carl Sturtivant wrote:
I'm not sure I'm following what you exactly have done here but in
general this is what needs to be done to make dynamic libraries
properly work in D :
* Initialize module infos (module constructors and similar)
* Add TLS variables
* Add exception handling tables
* Add GC roots
The above four things need to be extracted from the loaded dynamic
library and it gets loaded and preferably remove them as well when the
dynamic library gets unloaded. Currently this is only extracted from
the running executable. This is platform dependent but usually it's
extracted using bracketed sections via extern C variables.
OK, good to know. Any further hints about these, or where I can look?
From druntime:
* rt.minfo - module infos. The "_moduleinfo_array" variable contains the
module infos.
* rt.deh2 - exception handling. On Mac OS X the "_deh_eh_array" contains
the exception handling tables. On the other Posix systems the sections
bracketed by "_deh_beg" and "_deh_end" contains the tables.
* rt.thread - threading, TLS. On Mac OS X the TLS variables are stored
in "_tls_data_array". On the other Posix systems they're are again
stored in bracketed sections: "_tlsstart" and "_tlsend".
* rt.memory - GC roots. I think this module contains code related to
adding GC roots. rt.memory_osx for Mac OS X.
You can also take a look at work by Martin Nowak:
https://github.com/dawgfoto/druntime/commits/SharedRuntime
What I've done is use the C dynamic loading library (header dlfcn.h) to
manually load a shared object written in D, dload.d, from a D program
(main.d), which then successfully calls functions in dload.d that are
not defined extern(C).
I am attempting a do-it-yourself dynamic loading in D, where I
explicitly do all the administration manually to make it work, rather
than rely upon D to do it automatically. Hence my use of the C dynamic
loading library, which knows nothing of additional work D must do.
The functions from dlfcn.h is what D would use as well. Possibly wrapped
in some D function that does some additional work.
--
/Jacob Carlborg
