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    <p>Scratched my head thinking of what a short-but-complete example of sharing memory between two applications might be. The only option is a console application, GUI applications require a minimum of 3 files (DPR + PAS + DFM). So I cooked up a small example where one integers array is shared using a memory mapped file (backed by the page file so I don't need to have a phisical file on disk for this to work). The console application responds to 3 commands:</p> <ul> <li><strong>EXIT</strong></li> <li><strong>SET NUM VALUE</strong> Changes the value at index <strong>NUM</strong> in the array to <strong>VALUE</strong></li> <li><strong>DUMP NUM</strong> displays the value in the array at index <strong>NUM</strong></li> <li><strong>DUMP ALL</strong> displays the whole array</li> </ul> <p>Of course, the command processing code takes up about 80% of the whole application. To test this compile the following console application, find the executable and <em>start it twice</em>. Go to the first window and enter:</p> <pre><code>SET 1 100 SET 2 50 </code></pre> <p>Go to the second console and enter this:</p> <pre><code>DUMP 1 DUMP 2 DUMP 3 SET 1 150 </code></pre> <p>Go to the first console and enter this:</p> <pre><code>DUMP 1 </code></pre> <p>There you have it, you've just witnessed sharing memory between two applications.</p> <pre><code>program Project2; {$APPTYPE CONSOLE} uses SysUtils, Windows, Classes; type TSharedArray = array[0..10] of Integer; PSharedArray = ^TSharedArray; var hFileMapping: THandle; // Mapping handle obtained using CreateFileMapping SharedArray: PSharedArray; // Pointer to the shared array cmd, s: string; num, value, i: Integer; L_CMD: TStringList; function ReadNextCommand: string; begin WriteLn('Please enter command (one of EXIT, SET NUM VALUE, DUMP NUM, DUMP ALL)'); WriteLn; ReadLn(Result); end; begin try hFileMapping := CreateFileMapping(0, nil, PAGE_READWRITE, 0, SizeOf(TSharedArray), '{C616DDE6-23E2-425C-B871-9E0DA54D96DF}'); if hFileMapping = 0 then RaiseLastOSError else try SharedArray := MapViewOfFile(hFileMapping, FILE_MAP_READ or FILE_MAP_WRITE, 0, 0, SizeOf(TSharedArray)); if SharedArray = nil then RaiseLastOSError else try WriteLn('Connected to the shared view of the file.'); cmd := ReadNextCommand; while UpperCase(cmd) &lt;&gt; 'EXIT' do begin L_CMD := TStringList.Create; try L_CMD.DelimitedText := cmd; for i:=0 to L_CMD.Count-1 do L_CMD[i] := UpperCase(L_CMD[i]); if (L_CMD.Count = 2) and (L_CMD[0] = 'DUMP') and TryStrToInt(L_CMD[1], num) then WriteLn('SharedArray[', num, ']=', SharedArray^[num]) else if (L_CMD.Count = 2) and (L_CMD[0] = 'DUMP') and (L_CMD[1] = 'ALL') then begin for i:= Low(SharedArray^) to High(SharedArray^) do WriteLn('SharedArray[', i, ']=', SharedArray^[i]); end else if (L_CMD.Count = 3) and (L_CMD[0] = 'SET') and TryStrToInt(L_CMD[1], num) and TryStrToInt(L_CMD[2], value) then begin SharedArray^[num] := Value; WriteLn('SharedArray[', num, ']=', SharedArray^[num]); end else WriteLn('Error processing command: ' + cmd); finally L_CMD.Free; end; // Requst next command cmd := ReadNextCommand; end; finally UnmapViewOfFile(SharedArray); end; finally CloseHandle(hFileMapping); end; except on E: Exception do Writeln(E.ClassName, ': ', E.Message); end; end. </code></pre>
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    1. CO@Cosmin, Why I can't show all items using looping? It shows many 0. `for j := low(SharedArray^) to high(SharedArray^) do WriteLn(SharedArray^[j]);'. I need to match a specific data with the array. I just tried looping, I hope the shared arary can work with binary search.
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    2. COThe shared block of memory is nothing magic, it's just a shared block of memory. You can implement whatever algorithm you want using it. It shows lots of zeros because the block of memory is zero-initialized.
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    3. COCosmin, I tried to show all items but I see ^only^ lots of zeros.
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