数组 – 在Delphi中的两个应用程序之间共享数据数组

我想到了两个应用程序之间共享内存的简短但完整的例子.唯一的选择是控制台应用程序,GUI应用程序至少需要3个文件(DPR PAS DFM).所以我编写了一个小例子,其中一个整数数组使用内存映射文件共享(由页面文件支持,所以我不需要在磁盘上有一个phisical文件来实现).控制台应用程序响应3个命令：

>退出
> SET NUM VALUE将数组中索引NUM处的值更改为VALUE
> DUMP NUM在索引NUM处显示数组中的值
> DUMP ALL显示整个阵列

当然,命令处理代码占整个应用程序的大约80％.要测试此编译以下控制台应用程序,请找到可执行文件并启动它两次.转到第一个窗口并输入：

SET 1 100
SET 2 50

转到第二个控制台并输入以下内容：

DUMP 1
DUMP 2
DUMP 3
SET 1 150

转到第一个控制台并输入：

DUMP 1

你有它,你刚刚目睹了两个应用程序之间共享内存.

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,SizeOf(TSharedArray),'{C616DDE6-23E2-425C-B871-9E0DA54D96DF}');
    if hFileMapping = 0 then
      RaiseLastOSError
    else
      try
        SharedArray := MapViewOfFile(hFileMapping,FILE_MAP_READ or FILE_MAP_WRITE,SizeOf(TSharedArray));
        if SharedArray = nil then
          RaiseLastOSError
        else
          try
            WriteLn('Connected to the shared view of the file.');

            cmd := ReadNextCommand;
            while UpperCase(cmd) <> '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[',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.