Re: Shared library in Ada

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

Sebastien <seb.morand@gmail.com> writes:
>> Yes I'm running Gnat on FreeBSD.
>> Thanks about this link, I didn't know.
>
> I follow the instruction and did the sample thing:

[snipped]

- Since both your library and your test program are in Ada, you don't
  need pragma Import or pragma Export.

- You do not need to duplicate the mylib.ads file.

- If you're going to use project files, you should go all the way and
  define a library project file for your library, and use that to
  build the library.

The library:

package My_Lib is
   pragma Preelaborate;
   procedure Print;
end My_Lib;

with Ada.Text_IO;
package body My_Lib is
   procedure Print is
   begin
      Ada.Text_IO.Put_Line ("Hello, World.");
   end Print;
end My_Lib;

project My_Lib is
   for Source_Dirs use ("my_lib");
   for Object_Dir use "my_lib.o";
   for Library_Name use "mylib";
   for Library_Kind use "dynamic";
   for Library_Dir use "lib";
   for Externally_Built use "false";
end My_Lib;

You then build the library like this:

gnatmake -Pmy_lib

This will produce ./lib/libmylib.so.

Then, the client:

with My_Lib;
procedure Main is
begin
   My_Lib.Print;
end Main;

with "my_lib";
project Main is
   for Source_Dirs use (".");
   for Main use ("main");
end Main;

You would build your client program like this:

gnatmake -Pmain

which will link main dynamically with lib/libmylib.so.

-- 
Ludovic Brenta.