On 11/02/2013 16:06, Regan Heath wrote:
On Sun, 10 Feb 2013 12:36:38 -0000, Ben Davis <ent...@cantab.net> wrote:
DllMain is a weird one - it creates all sorts of linker errors if I
try it with extern(C) instead of extern(Windows) (which is different
from the other methods, which compile fine with extern(C) and then
crash at runtime).
extern(C) will change the mangling.. so in this case I guess the linker
is expecting DllMain but the mangling is incorrect. I wonder if the
compiler detects the presence of DllMain and alters the linker line.
DMD has a command line option to output the linker command line, maybe
see if it changes with/without a DllMain in the code perhaps.
I think that's exactly what's going on. If it was only the mangling, I'd
expect one error relating to that function, but instead I get at least
10 errors relating to various functions I've never heard of. I don't
think there's any particular need to test further.
Also it doesn't matter what name I export it by or whether I export it
at all. I'm getting the feeling this is what was implied by "The
presence of DllMain() is recognized by the compiler". Good to know
anyway - I like to keep stuff clean :)
Yep, DllMain isn't a requirement, but if is present should be called by
the C runtime when the dll is loaded. You can hook into process
start/stop and thread attach/detach with dll main. It's good for thread
local storage initialisation - for example.
Yep, sounds about right - and it sounds like something that gets
resolved in a special way when the DLL is linked. Certainly DllMain
isn't appearing in my export table, yet I've established (by calling
MessageBoxA from inside DllMain - that was brave of me, wasn't it? :P)
that it is being called. :)
