How to check if port is usable in Inno Setup?

Question

I need to check some port is usable or not? How can do that in Inno Setup? Is there any way to use socket in to Inno Setup? Is there any library for this? If there how can

Answer 1

Function to return (in MsgBox) service or program that use port 80. MsgBox will not shown if output is empty.

function NextButtonClick(CurPage: Integer): Boolean;
var
  TmpFileName, ExecStdout: string;
  ResultCode: integer;
begin
  if CurPage = wpWelcome then
  begin
    TmpFileName := ExpandConstant('{tmp}') + '\~pid.txt';
    Exec('cmd.exe',
         '/C FOR /F "usebackq tokens=5 delims= " %i IN (`netstat -ano ^|find "0.0:80"`) DO '
           + '@tasklist /fi "pid eq %i" | find "%i" > "' + TmpFileName + '"', '', SW_HIDE,
         ewWaitUntilTerminated, ResultCode);
    if LoadStringFromFile(TmpFileName, ExecStdout) then
    begin
      MsgBox('Port 80 is used by '#13 + ExecStdout, mbInformation, MB_OK);
    end;
    DeleteFile(TmpFileName);
  end;
  Result := True;
end;