with System;
with Text_Io;

procedure A_Test is

  Command : constant String := "echo Hello World &" & Ascii.Nul;
  Status : Integer;


  ---------------------------------
  -- System shell command interface
  ---------------------------------
  function Shell_Cmd (Command : in System.Address) return Integer;
  pragma Import (C, Shell_Cmd, "system");


  ------------------
  -- Start 2 threads
  ------------------
  task Task1 is
    entry Start_Task;
  end Task1;

  task Task2 is
    entry Start_Task;
  end Task2;

  task body Task1 is
  begin
    select  -- Task 1
      accept Start_Task;
    or
      terminate;
    end select;
  end Task1;

  task body Task2 is
  begin
    select  -- Task 2
      accept Start_Task;
    or
      terminate;
    end select;
  end Task2;


  procedure My_Routine is
  begin
    Text_Io.Put_Line ("Program successful");
  end My_Routine;


begin
  Status := Shell_Cmd (Command'Address);

  --------------------------------------------------------------
  -- From "gvd" set break point on line below by selecting line.
  -- Run program by clicking "Run" button, some warnings are
  -- logged and process goes into limbo.
  --
  -- Note, it appears to work if you "gdb" command line to set
  -- break point as follows: "b My_Routine".
  -- However, it does NOT work using "b 50".
  -- Turns out that "gdb" works intermittently, only.
  --
  -- Another interesting anomoly is that the process never seems
  -- to quit when run from "gvd" or "gdb" and no break points,
  -- but does run to completion without the debugger.
  --------------------------------------------------------------
  My_Routine;
end A_Test;