On Wednesday, 5 February 2014 at 16:27:10 UTC, Benjamin Thaut
wrote:
Am 05.02.2014 16:36, schrieb Jeroen Bollen:
On Wednesday, 5 February 2014 at 13:52:10 UTC, Benjamin Thaut
wrote:
Am 05.02.2014 14:21, schrieb Jeroen Bollen:
Is it possible to load in a dynamic library in D, and have
the library
you just loaded call your own functions? Imagine having a
plugin loader
and the plugins call methods like 'addButton()' from the host
application.
Yes, thats what core.runtime.loadLibrary is for.
http://dlang.org/phobos/core_runtime.html#.Runtime.loadLibrary
You can also always fall back to operating system functions
like,
LoadLibrary and GetProcAddress for windows.
Kind Regards
Benjamin Thaut
How exactly does that work 2 ways? Can I just define the
functions and
not implement them in the library?
You don't define functions, just function pointers. You could
also do it oop style:
// The loader
import core.sys.windows.windows;
interface IPlugin
{
void pluginMethod1();
void pluginMethod2();
}
// function pointer definition for the entry function
extern(C) alias IPlugin function() pluginEntry;
IPlugin loadPlugin(const(char)[] path)
{
auto handle = cast(HMODULE)runtime.loadLibrary(path);
//use dlsym on linux
auto entry = cast(pluginEntry)GetProcAddress(handle,
"pluginEntry".ptr);
return entry(); // get the plugin interface
}
// The plugin
interface IPlugin
{
void pluginMethod1();
void pluginMethod2();
}
class PluginImpl : IPlugin
{
override void pluginMethod1() { ... }
override void pluginMethod2() { ... }
}
export extern(C) IPlugin pluginEntry()
{
return new PluginImpl();
}
This however will have issues on windows, because the runtime
is not shared. On Linux it should work just fine if you
remember to link against the shared runtime.
You might also want to watch this talk from D-conf 2013:
http://dconf.org/2013/talks/nowak.html
Kind Regards
Benjamin Thaut
I think Jeroen is asking for the opposite of this as library will
call host's functions.
