What's the cause of extra new line with Text_IO when program exit

["Zhu, Qun-Ying" <zhu.qunying@gmail.com>]

Hi,

I have known this problem for quite some time, but did not really know 
why it behave like this.

These two programs:
======================================================================
-- hello.adb
with Ada.Text_IO; use Ada.Text_IO;

procedure Hello is
begin
     Put("Hello");
     Put(" ");
     Put("World!");
end Hello;

-- hello_stream.adb
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Text_IO.Text_Streams; use Ada.Text_IO.Text_Streams;

procedure hello_stream is
     std_out   : Stream_Access;
begin
     std_out := Stream (Standard_Output);

     String'Write (std_out, "Hello");
     String'Write (std_out, " ");
     String'Write (std_out, "World!");
end hello_stream;
==================================================================

When executing, they have different behavior.

For hello, you have:
# ./hello
Hello World!
#

While for hello_stream, you got:
# ./hello_stream
Hello World!#

If change the last Put to Put_Line for hello, you got the same result.
I would like to know why it is like that.