Delphi API Socket通讯接收不到数据。

Question

to truexf :用TCP&UDP测试工具 做的服务器。我在测试工具中发的数据.这边程序就是收不到数据。 

Answer 1

那你收什么？既然服务器没有数据发过来你的recv函数就会阻塞在哪里

Answer 2

先确定服务器端是否有返回数据，另外，不要在非主线程中操作vcl，例如118行就是错误的用法。

Answer 3

to truexf:啥都没收到。
我把
 BeginThread(nil, 0, @Receive, PChar(skt),0, dThreadID);
改成
 BeginThread(nil, 0, @Receive, nil,0, dThreadID);procedure Receive(Sock :TSocket);stdcall;改成
procedure Receive();stdcall;可以接受到数据了，Why?

Answer 4

to pathletboy:嗯，好的，我记住了，我这个是练手程序，以前没用过API写SOCKET.这里调通了，再写到其他地方去的。

Answer 5

你线程函数的定义不对
function BeginThread(SecurityAttributes: Pointer; StackSize: LongWord;
  ThreadFunc: TThreadFunc; Parameter: Pointer; CreationFlags: LongWord;
  var ThreadId: LongWord): Integer;type
  TThreadFunc = function(Parameter: Pointer): Integer;这么定义
function Receive(Sock :TSocket): Integer;

Answer 6

to truexf:
to pathletboy:
  感谢你们2位，问题解决了，线程函数多加了个stdcall导致接收不到数据。 

Answer 7

delphi默认是pascal传参方式，前3个参数用寄存器，然后再用堆栈传参，stdcall是直接用堆栈传参，你线程函数定义为堆栈传参的话是无法接收到正确的参数的。

Answer 8

to pathletboy :学习了，我单步调的时候我也看到了Sock的值变了，我就没传参了，我后来临时一想，改成我上面的那样，也可以收到数据，就是没注意到stdcall，pathletboy正解。

Answer 9

Delphi API Socket 发送，接收十六进制数据 代码调通的贴下面了。unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, WinSock, StdCtrls;type
  TSocketComm=class(TObject)
  private  public
    constructor Create;
    destructor Destroy; override;
    function ConnectSvr: Integer;
    function SendFrame(Str_SendFrame: string): Integer;
  end;type
  TForm1 = class(TForm)
    btn1: TButton;
    btn2: TButton;
    edt_SendFrame: TEdit;
    mmo_Debug: TMemo;
    btn3: TButton;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure btn3Click(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form1: TForm1;
  skt:TSocket;
  LExit:Boolean;
  Svr_Addr,Clnt_Addr:TSockAddr;
  ClientSocket:TSocketComm;procedure Receive(Sock:TSocket);implementation{$R *.dfm}constructor TSocketComm.Create;
var
    Wsa:TWSAData;
begin
    inherited Create;
    if WSAStartup(MakeWord(2,2),Wsa)<>0 then
    begin
        ShowMessage('Init Socket failed');
        WSACleanup;
    end;
end;destructor TSocketComm.Destroy;
begin
    inherited destroy;
    WSACleanup;
    closesocket(skt);
end;function TSocketComm.ConnectSvr():Integer;
var
    dThreadID:DWORD;
    i_RtnCode:Integer;
begin
    skt:=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if skt=INVALID_SOCKET then
    begin
        ShowMessage('Create Socket failed');
        WSACleanup;
        Exit;
    end;
    Clnt_Addr.sin_family:=AF_INET;
    Clnt_Addr.sin_addr.S_addr:=inet_addr('127.0.0.1');
    Clnt_Addr.sin_port:=htons(StrToInt('2039'));
    bind(skt,Clnt_Addr,SizeOf(Clnt_Addr));    Svr_Addr.sin_family:=AF_INET;
    Svr_Addr.sin_addr.S_addr:=inet_addr('192.168.200.95');
    Svr_Addr.sin_port:=htons(StrToInt('2038'));
    i_RtnCode:=connect(skt,Svr_Addr,SizeOf(Svr_Addr));    if i_RtnCode<>0 then
    begin
        ShowMessage('Connect 192.168.200.95 failed');
        WSACleanup;
        Exit;
    end;
    LExit:=False;
    BeginThread(nil, 0, @Receive, PChar(skt),0, dThreadID);
end;procedure Receive(Sock:TSocket);
var
  Buffer: pChar;
  i,iRes: Integer;
  S,Str_RecByte:string;
  i_Buf:array[1..1024] of Byte;
begin
    GetMem(Buffer, 1024);
    while not LExit do
    begin
        iRes := recv(Sock, Buffer^, 1024, 0);
        if iRes < 1 then
        begin
            Sleep(500);
            Continue;
        end;
        Move(Buffer^,i_Buf,iRes);
        for i:=1 to iRes do
        begin
            Str_RecByte:=IntToHex(i_Buf[i],2);
            S:=S+' '+Str_RecByte;
        end;
        if Copy(S,1,1)=' ' then
        begin
            Delete(S,1,1);
        end;
        Form1.mmo_Debug.Lines.Add(S);
        ZeroMemory(Buffer, 1024);
    end;
    FreeMem(Buffer);
   // CloseSocket(skt);
    ExitThread(0);
end;function TSocketComm.SendFrame(Str_SendFrame:string):Integer;
var
    i,i_FrameLen:Integer;
    i_Buf:array[1..1024] of Byte;
begin
    Str_SendFrame:=StringReplace(Str_SendFrame,' ','',[rfReplaceAll]);
    i_FrameLen:=Length(Str_SendFrame) div 2;              //Convert string to byte string
    for i:=0 to i_FrameLen-1 do
    begin
        i_Buf[i+1]:=StrToInt('$'+Copy(Str_SendFrame,i*2+1,2));
    end;
    send(skt,i_Buf,i_FrameLen,0);
end;procedure TForm1.btn1Click(Sender: TObject);
begin
    ClientSocket:=TSocketComm.Create;
    ClientSocket.ConnectSvr;
end;procedure TForm1.btn2Click(Sender: TObject);
begin
//    closesocket(skt);
    WSACleanup;
end;procedure TForm1.btn3Click(Sender: TObject);
begin
    ClientSocket.SendFrame(Trim(edt_SendFrame.Text));
end;procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
    btn2Click(nil);
end;end.