Enumerating a List of systems Com Ports in Delphi

Question

Objective: I would like to be able to list the available COM Ports on a system in Delphi.

Homework: I have read this SO thread on enumerating the LPT ports of a system using the registry. I have also found that the COM ports are listed in the registry at HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM but found unanswered gesticulation in the same thread that this might not be reliable on different machines and different versions of windows.

I also found articles referencing the use of QueryDosDevice() but upon trying this sample code, I found that it did not appear to list any COM ports at all.

Question: What is the most reliable way (across unknown Windows Versions) to list the COM ports on a Windows Machine?

Answer 1

DEVICEMAP\SERIALCOMM is good for all NT versions. You'll probably need to look under DYN_DATA for Win9x.

Use this method if you need runtime reliability.

Answer 2

Please try this code :

function GetSerialPortNames: string;
var
  Index: Integer;
  Data: string;
  TmpPorts: String;
  sr : TSearchRec;
begin
  try
    TmpPorts := '';
    if FindFirst('/dev/ttyS*', $FFFFFFFF, sr) = 0 then
    begin
      repeat
        if (sr.Attr and $FFFFFFFF) = Sr.Attr then
        begin
          data := sr.Name;
          index := length(data);
          while (index > 1) and (data[index] <> '/') do
            index := index - 1;
          TmpPorts := TmpPorts + ' ' + copy(data, 1, index + 1);
        end;
      until FindNext(sr) <> 0;
    end;
    FindClose(sr);
  finally
    Result:=TmpPorts;
  end;
end;

I tried this code in Win XP. Don't know the other OS. (I advice SYNAPSE library for network communication application.)

Answer 3

Please go through URL which is written in C++

http://www.codeproject.com/KB/system/serial_portsenum_fifo.aspx

and same approach can be implemented in delphi too.. or somebody can convert for you in SO..

This will work for all windows versions since this works from the principle of device manager which is available for all window versions.