Re: Win NT + Object Ada: serial port I/O

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

lynch@cci.de wrote in message <7abh8g$bvh$1@nnrp1.dejanews.com>...
>In article <79cu2a$4iu$1@nnrp1.dejanews.com>,
>  dennison@telepath.com wrote:
>> In article <79952r$2t$1@nnrp1.dejanews.com>,
>>   lynch@cci.de wrote:
>> > Does anyone have any information/experience programming serial ports in
Ada
>on
>> > a Windows platform? I can think of two ways to do this:

On Windows NT, I use Ordinary File IO -- i.e. I open the file "COM2:" (or
whatever),
using  Gnat.Os_Lib.Open_Read_Write to get a file descriptor.

It should be easy to port the Gnat.OS_lib functions needed to compile with
other Ada compilers, for it uses pragma interface to the C library.

To deal with the ports settings, I write a file called _portsu.bat "on the
fly" with parameters supplied by my program.  Here's an example of
_portsu.bat:
@echo off
mode COM2 baud=2400 data=8 parity=N stop=1

I then execute this batch file with a call to the following subprogram:
----------------------------------------------------------------------------
----
with Interfaces.C;
function Execute_Shell_Command (The_Command_String : String)
      return Interfaces.C.Int is
   Rcsid : constant String:=
      "$Id: execute_shell_command.adb,v 1.3 1998/03/30 02:29:50 dave Exp $";
   package C renames Interfaces.C;
   function System (S : C.Char_Array) return C.Int;
   pragma Import (C, System, "system");
begin
   return System (C.To_C (The_Command_String));
end Execute_Shell_Command;
----------------------------------------------------------------------------
----

The call to the subprogram looks like:
The_Command_Status := Execute_Shell_Command ("_portsu > nul");

When doing serial port programming on Unix systems, I use the Florist
bindings to Posix functions for performing these operations, but when I had
to do it for Win NT, I was in a hurry, and needed something I knew how to
do, so I use this "kludge" -- but it works.

One day, I'll figure out how to do it directly.

The mode setting needs to be done before the file is opened.

I hope this helps.

David C. Hoos, Sr.