Re: How to kill GNAT DLL initialization?

[ahlan.marriott@gmail.com]

On Wednesday, 10 August 2016 14:52:33 UTC+2, Dmitry A. Kazakov  wrote:
> As it seems GNAT DLL may not have initialization code invoked in 
> DllMain. This inevitable deadlocks RTS. Removing user library-level 
> tasks does not help. The RTS itself contains library-level tasks. E.g. 
> when asynchronous select is used.
> 
> Now the question is how to kill calls to initialization code from DllMain.
> 
>     for Library_Auto_Init use "false";
> 
> Is not enough. Are there other attributes I missed?
> 
> (Maybe there is a way to remove DllMain from the external symbols list 
> during linking?)
> 
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de

Dear Dmitry,

We produce DLLs written using GNAT that are used by other languages - typically C++
We don't explicitly run any initialisation code, the main procedure is always empty.
(although this is probably a left over from our ObjectAda days)
If something has to be initialised then we put this into a procedure, export it and request that our C++ user calls this before calling any other routine.

Here is a typical Gpr file for one of our Dlls.

-------
project Monitor is

   package Naming is
      for Casing use "mixedcase";
   end Naming;

   for Library_Name use "Monitor";
   for Shared_Library_Prefix use "";

   for Source_Dirs use ("W:\Source\Ada\Interfaces\Monitor",
                        "W:\Source\Ada\Interfaces",
                        "W:\Source\Ada\Shared",
                        "W:\Source\Ada\Open\Shared",
                        "W:\Source\Ada\Open\Shared\Windows");

   for Library_Interface use ("Monitor_Interface");

   for Object_Dir use "objects";

   for Library_Options use ("-LW:\Product\Windows", "resources.o");
   for Library_Dir use "W:\Product\Windows";
   for Library_Ali_Dir use "D:\Binary\Ada\Interfaces\Monitor";
   for Library_Kind use "dynamic";
   for Library_Standalone use "encapsulated";

   package Pretty_Printer is
      for Default_Switches ("ada") use ("-i2", "-M120", "-aL", "-A1", "-A4");
   end Pretty_Printer;

   package Builder is
      for Default_Switches ("ada") use ("-s", "-g");
   end Builder;

   package Compiler is
      for Default_Switches ("ada") use
         ("-O1", "-gnatQ", "-gnata", "-gnato", "-g", "-gnat12",
          "-gnatwcehijkmopruvz.c.n.p.t.w.x", "-gnatykmpM120");
   end Compiler;

   package Binder is
      for Default_Switches ("ada") use ("-E");
   end Binder;

end Monitor;

-------

and the main package.

-------
with Monitor_Interface; --> UD: Drag in Code

procedure Monitor is
begin
  null;
end Monitor;
-------

Monitor_Interface ads exports all the procedures that the DLL provides and the Adb implements them.

Hoping this helps,
MfG
Ahlan