Question

I have Delphi lib which must return information read via socket.

function GetBufferInfo(Address: PChar): PChar; export; stdcall;
var
  BD: TBufferData;
begin
  BD := TBufferData.Create;
  Result := PChar(TBufferData.GetData);
  BD.Free;
end;

TBufferData class has a method ReadData which is being called when socket Read event fires. So it can be called several times until all info is read. The problem is how to wait while information is being read and don’t go out of GetBufferInfo method. I thought about threads but don’t know how exactly it can be done.

I created a small example which demonstrates the issue:

program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils, Classes, Windows;

type
  TBufferData = class
  private
    FResult: string;
  public
    constructor Create;
    procedure ReadData(Sender: TObject; Buf: string; var Size: Integer);
    function GetData: string;
  end;

{ TBufferData }

var
  BD: TBufferData;
  s: string;
{ TBufferData }

constructor TBufferData.Create;
begin
  FResult := 'Some text received via socket';
end;

function TBufferData.GetData: string;
begin
  Result := FResult;
end;

procedure TBufferData.ReadData(Sender: TObject; Buf: string; var Size: Integer);
begin
  //info is being received from socket
  FResult := FResult + Buf;
end;

begin
  BD := TBufferData.Create;
  s := BD.GetData;
  Writeln(s);
  BD.Free;
  Readln;
end.

Thanks in advance
Yura

Answer 1

Application.ProcessMessages for console would look like this. State flag will be set outside.

while State <> stDone do begin
  ...
  ProcessMessages;
end;

procedure ProcessMessages;
var
  Msg: TMsg;
begin
  if PeekMessage(Msg,0,0,0,0) then begin
    GetMessage(Msg,0,0,0);
    DispatchMessage(Msg);
  end;
  Sleep(10);//sleep to avoid 25% processor decrease
end;