API SendMessage Help

I see now that this involves creating a mapped file..  
Still could use an example though...

type sendmessage in delphi. press F1 and you will get help on the function.

Now you should know what message you want to send(receive).
If you dont, tell what you want to do and may be I can help

:) I seen that it's 500 point question (too big for what I mean). May be I misunderstand the question, so you should ask more clearly :)

I want to pass a string to mirc.exe in a mapped file via Sendmessage.

Mirc wants it in this format..
SendMessage(mHwnd, WM_MCOMMAND, cMethod, 0L)
...
WM_MCOMMAND - which should be defined as WM_USER + 200
^^ this is causing me some trouble, need to declare some kind of varible to use there.  

I tried..  wmC: LongInt = WM_USER + 200;
but it doesn't seem to work.


----------
Second half.

I created a mapped file as instructed, now I need to set a string of variable length as data inside the mapped file.  The mapped file needs to be 1024 bytes in length.

Here is what I tried.

hMapFile := CreateFileMapping($FFFFFFFF,
    nil,  Page_ReadWrite, 0,
    SizeOf(byte) * 1024, 'mIRC');

if hMapFile = 0 then
  raise Exception.Create('Error creating Mapped File.');

 ShareData := MapViewOfFile(hMapFile,
    File_Map_Write, 0, 0, SizeOf(byte) * 1024);

-------
That part SEEMS to work.

Now I want to...
  ShareData^ := 'My text string';
   ^^  This is very wrong.

-------  

500 points for being a multipart question.

_________________________
APPENDIX from the mirc help file

The following call to SendMessage() makes mIRC perform the commands that you specify.

   SendMessage(mHwnd, WM_MCOMMAND, cMethod, 0L)

   mHwnd - the handle of the main mIRC window, or the handle of a Channel, Query, etc. window.

   WM_MCOMMAND - which should be defined as WM_USER + 200

   cMethod - the way in which you want mIRC to process the message, where:
        1 = As if typed in editbox
        2 = As if typed in editbox, send as plain text
        4 = Use flood protection if turned on, can be or'd with 1 or 2

   Returns - 1 if success, 0 if fail




The application that sends these messages must create a mapped file named mIRC with CreateFileMapping().

When mIRC receives the above messages, it will open this file and use the data that this mapped file contains to perform the command or evaluation. In the case of an evaluation, mIRC will output the results to the mapped file.

The mapped file must be at least 1024 bytes in length.

it's weird that lParam isn't used


var ShareData: PChar = nil;


ShareData := MapViewOfFile(hMapFile,
   File_Map_Write, 0, 0, SizeOf(byte) * 1024);

StrPLCopy(ShareData, MyString, Length(MyString));

if SendMessage(hWinMirc, WM_MCOMMAND, cMethod, 0) = 1 then
  ResultString:=string(ShareData); // in case of a query function

hope it helps :)

Still not working..  here's my code.
---------------------------------------
var
  Form1: TForm1;
  ChanList: TStringlist;
  MircHandle: LongInt;
  hMapFile: THandle;
  ShareData: PChar = nil;
  mCOMMAND: LongInt = WM_USER + 200;
  MC: LongInt;

const
 VirtualName = 'mIRC';

implementation

{$R *.dfm}

Procedure TForm1.FormCreate(Sender: TObject);
Begin
 ChanList := TStringlist.Create;
 UpdateActives1Click(self);
 MC := WM_USER + 200;
 hMapFile := CreateFileMapping($FFFFFFFF, nil, Page_ReadWrite, 0, SizeOf(byte) * 1024, virtualname);
 if hMapFile = 0 then
  raise Exception.Create('Error creating Memory Mapped File, this program can only be run in WinNT, 2000 or XP');
  ShareData := MapViewOfFile(hMapFile, File_Map_Write, 0, 0, SizeOf(byte) * 1024);
End;

Procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
Begin
 ChanList.Free;
 UnMapViewOfFile(Sharedata);
 CloseHandle(hMapFile);
End;

function TForm1.TaskList(FirstHandle: THandle; ListAll: Boolean): string;
var
  lngLen:longint;
  strBuffer, This, All:string;
  TaskHandle: THandle;
begin
  MircHandle := 0;
  cbChans.ItemIndex := -1;
  cbChans.Items.Clear;
  ChanList.Clear;
  TaskHandle := GetWindow(FirstHandle,GW_HWNDFIRST);
  while TaskHandle > 0 do
  begin
     if (TaskHandle <> FirstHandle) and (TaskHandle <> Application.Handle) then
     begin
        lngLen := GetWindowTextLength(TaskHandle) + 1;
        SetLength(strBuffer,lngLen);
        lngLen := GetWindowText(TaskHandle,PChar(strBuffer),lngLen);
        if lngLen > 0 then
        begin
           This := TrimRight(strBuffer);
           if pos('#',This) = 1 then
             begin
             ChanList.Append(IntToStr(TaskHandle));
             cbChans.Items.Append(Copy(This,1,(pos(' ',This)-1)));
             end;
          if pos('mIRC',This) = 1 then MircHandle := TaskHandle;
        end;
     end;
     TaskHandle := GetWindow(TaskHandle,GW_HWNDNEXT);
  end;
  if MircHandle = 0 then ShowMessage('Mirc Handle Not found!');
end;

Procedure TForm1.UpdateActives1Click(Sender: TObject);
Begin
  TaskList(Application.Handle,TRUE);
  if cbChans.Items.Count > 0 then cbChans.ItemIndex := 0;
End;

procedure TForm1.buttonSendThisClick(Sender: TObject);
 var T: String;
Begin
 T := '/msg _Psych Hello!';
 StrPLCopy(ShareData, T,Length(T));
 if SendMessage(mirchandle,MC,2,0) = 0
  then Showmessage('SendMessage returned ERROR!');
End;

procedure TForm1.GetShareData(P: Pchar);
Begin
  // TODO
End;

procedure TForm1.SetShareData(P: PChar);
Begin
  // TODO
End;

procedure TForm1.Exit1Click(Sender: TObject);
Begin
  Application.Terminate;
End;

END.

You simply send a message to mIRC and it starts to handle the mapped file.
"WM_MCOMMAND - which should be defined as WM_USER + 200"
is simply the Windows message to send.

const
  WM_MCOMMAND = WM_USER+200;


There is NO way to send a string through any Windows message parameter except WM_COPYDATA.

Check this out

http://necroman.wot.net/dllhelp.htm#_SendMessage

It seems to use WM_USER + 201 instead, though.

Works fine.  Thank you!

Thanks to everyone else as well.  If I had enough points to spread around I'd give you all the same.  

Don