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From: "Rego, P." <pvrego@gmail.com>
Newsgroups: comp.lang.ada
Subject: Using dll from a C# code
Date: Wed, 29 Feb 2012 03:52:48 -0800 (PST)
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Date: 2012-02-29T03:52:48-08:00
List-Id: <comp.lang.ada>

Hello,

I have a method in C# which I need to export to Ada using a dll. Maybe 

// simple.cs
// compile with csc /t:library simple.cs
using System;
public class VerifyClass{
	public bool Verify(){
		return true;
	}
}

In order to use the function Verify() in Ada, I need to import this to something like 
-- simple.ads
package Simple is
	function Verify return Boolean;
	pragma Import
	(Convention    => dll,
	Entity        => Verify,
	External_Name => "Verify");
end Simple;

And I could use with 
-- main.adb
-- build with gnatmake main -largs -lsimple
with Text_IO; use Text_IO;
with Simple; use Simple;
procedure Main is
begin
	Put_Line (Boolean'Image (Verify));
end Main;	


When I build the Ada with 
gnatmake main -largs -lsimple

the compiler returns me 
./main.o(.text+0xd6):main.adb: undefined reference to `Verify@0'

So what have I missed? Maybe the C# code structure should be changed?