Delphi-iocp learning notes === learning iocp from scratch

Previously, software directly engaged in enterprise management had less access to networks. Network knowledge is also miserable.

Recently I Want To Get iocp. I found a lot of information online, mostly about C ++. Delphi is rarely used.

After reading this, I am not familiar with cainiao learning!

I read fxh's blog and thought it was easy to understand.

Http://fxh7622.blog.51cto.com/63841/7667

 

Basically, it is written according to his blog code. Compile and understand iocp principles.

 

First, let's take a general understanding.

1. The server creates an iocp port service.

2. The server creates n working threads and continuously processes the connections and requests on the port in turn.

3. Enable the iocp port service <bind the listening port to listen>. If a request is received, the iocp working thread is notified.

 

* When I first looked at people's code, I always wondered why I first created a working thread instead of enabling the port service.

<I understand it like this> If you enable the port service first, if there is a connection at this time and the worker thread is not ready yet, the request will be missed.

 

Well, let's start analyzing the code. <try to get rid of other code to make it clearer.>

 

 

 

   1:  var

   2:    WSData: TWSAData;

   3:    lvIOPort:THandle;

   4:    hThread, dwThreadId:DWORD;

   5:   

   6:    sSocket, cSocket:TSocket;

   7:    lvAddr:TSockAddr;

   8:    lvAddrSize:Integer;

   9:    lvMsg:String;

  10:    lvPort:Integer;

  11:   

  12:    lvSystemInfo: TSystemInfo;

  13:    i:Integer;

  14:    lvCount:Integer;

  15:  begin

  16:   

  17:    lvPort := 8988;

  18:   

19: // load the socket. Version 2.2 is used to facilitate heartbeat.

  20:    WSAStartup($0202, WSData);

  21:   

22: // create a complete port (Kernel Object)

  23:    lvIOPort := CreateIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0, 0);

  24:   

  25:   

26: // obtain System Information <Number of CPUs>

  27:    // GetSystemInfo(lvSystemInfo);

  28:    //lvCount := lvSystemInfo.dwNumberOfProcessors * 2 -1;

  29:   

30: // create a working thread for debugging

  31:    lvCount := 1;

  32:   

  33:    for I:=0 to lvCount do

  34:    begin

  35:       hThread := CreateThread(nil, 0, @ServerWorkerThread, 

  36:         Pointer(lvIOPort),0, dwThreadId);

  37:       if (hThread = 0) then

  38:       begin

  39:           Exit;

  40:       end;

  41:       CloseHandle(hThread);

  42:    end;

  43:   

  44:   

45: // create a socket, bind the socket to a port, and listen to the port.

  46:    sSocket:=WSASocket(AF_INET,SOCK_STREAM,0,Nil,0,WSA_FLAG_OVERLAPPED);

  47:    if sSocket=SOCKET_ERROR then

  48:    begin

  49:        closesocket(sSocket);

  50:        WSACleanup();

  51:    end;

  52:    lvAddr.sin_family:=AF_INET;

  53:    lvAddr.sin_port:=htons(lvPort);

  54:    lvAddr.sin_addr.s_addr:=htonl(INADDR_ANY);

  55:    if bind(sSocket,@lvAddr,sizeof(lvAddr))=SOCKET_ERROR then

  56:    begin

  57:       closesocket(sSocket);

  58:    end;

  59:   

  60:    listen(sSocket,20);

 

Specifically, serverworkerthread is a working function and runs in the thread mode.

// The next post analyzes the listener.