comdll.~dpr

Delphi7.0 封装的dll api串口源码

library COMdll;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, 
  StdCtrls;
Const 
Wm_CommNotify=WM_User+12;

var
  Hcom,Post_Event:Thandle;
  LpolW,LpolR:Poverlapped; 
 // RXComm:TComm;

{$R *.res}
Procedure Execute; 
var 
dwEvtmask,dwOvres,bb:Dword; 
RXFinish:Bool; 
begin 
  while true do 
  begin 
    DwEvtMask:=0; 
    RXFinish:=WaitCommEvent(hcom,dwevtmask,LpolR);   //等待串口事件EV_RXCHAR 
    if not RXFinish then               //如果返回True,已立即完成，否则继续判断 
      if GetLastError()=ERROR_IO_PENDING then //正在接收数据 
      begin 
        bb:=WaitForSingleObject(LpolR^.hEvent,500);//等待500ms 
        Case bb of 
          Wait_Object_0:  RXFinish:=GetOverLappedResult(hcom,LpolR^,dwOvRes,False); 
                           //返回False,出错 
          Wait_TimeOut:  RXFinish:=False;//定时溢出 
          else RXFinish:=False;   //出错 
        end; 
      end else RXFinish:=False; 
    if RXFinish then 
    begin 
      if WaitForsingleobject(Post_Event,infinite)=Wait_Object_0 then  //等待同步事件置位 
      begin 
        resetEvent(Post_Event);      //同步事件复位
       // PostMessage(self.handle,WM_CommNotify,0,0);  //发送消息
       //在这里可以触发串口接收事件
      end; 
    end; 
  end; 
end;


Procedure ComInit(com:PAnsiChar;baudrate,DataBit,stopBit,parity:integer;buf:longint);stdCall;
Var
Lpdcb:TDCB; 
begin 
  hcom:=createFile(com,   //串口名，可为com1-com4 
                 generic_read or Generic_write,//访问模式 
                 0,           //共享模式,必须为0 
                 nil,           //安全属性指针 
                    open_existing,   ///找开方式必须为open_existing 
                    File_Flag_Overlapped,//文件属性,本文设为交迭标志 
                    0);                 //临时文件句柄,必须为0   
  if hcom<>invalid_Handle_Value then 
  begin 
     SetupComm(hcom,buf,buf);          //设置缓冲区长度
     getCommState(hcom,lpdcb);           //设置串口 
     lpdcb.baudrate:=baudrate;
     lpdcb.stopbits:=stopBit;
     lpdcb.bytesize:=DataBit;
     lpdcb.parity:=parity; 
     setCommState(hcom,lpdcb); 
     SetCommMask(Hcom,ev_Rxchar);         //设置串口事件屏蔽 
  end else showMessage('无法打开串口！'); 
end;

Function WriteStr(const Str:String):Boolean;stdCall;            //发送数据
var 
DwCharsWritten,DwRes:Dword; 
S_DATA:String; 
BRes:boolean; 
Begin 
  BRes:=False; 
  S_Data:=Str; 
  if hcom<>INVALID_HANDLE_VALUE then 
  begin 
    DwCharsWritten:=0; 
    BRes:=WriteFile(Hcom,PChar(S_Data)^,Length(S_Data), 
              DwCharsWritten,LpolW);     //返回True，数据立即发送完成 
    if not BRes then 
    begin 
     if GetLastError()=Error_IO_Pending then 
       begin   //正在发送数据 
          DwRes:=WaitForSingleObject(LpolW^.hEvent,Infinite); 
          if DwRes=Wait_Object_0 then  // 如果不相等，出错 
             BRes:=GetOverLappedResult(hcom,LpolW^,DwCharsWritten,False)  //返回False,出错 
          else BRes:=true;   //数据发送完成 
       end; 
    end;
  end; 
  Result:=Bres; 
end; 

Procedure ReadStr(Var Msg:Tmessage);stdCall;      //接收数据
var 
 clear:boolean; 
 coms:TComStat; 
 cbNum,Cbread,lpErrors:Dword; 
 s:string; 
begin 
 clear:=clearCommerror(hcom,lperrors,@Coms); 
 if clear then 
 begin 
   cbnum:=Coms.cbInQue;    //获取接收缓冲区待接收字节数 
   setlength(s,cbnum+1);     //分配内存 
   ReadFile(hcom,PChar(S)^,cbnum,Cbread,LpolR);   //读串口 
   setlength(s,cbread);      //分配 
   SetEvent(Post_Event);     //同步事件置位 
 end; 
end;
procedure FreeMemo(Sender: TObject);stdcall   //释放内存
begin 
 CloseHandle(LpolW^.hEvent); 
 CloseHandle(LpolR^.hEvent); 
 dispose(lpolW); 
 dispose(lpolR); 
 LpolW:=Nil; 
 LpolR:=Nil;
 SetEvent(Post_Event); 
 CloseHandle(Post_Event); 
 CloseHandle(hcom); 
end;

procedure InitMemo();stdCall;  //初始化内存
begin
  New(lpolW); 
  New(lpolR); 
  LpolW^.Internal:=0; 
  LpolW^.InternalHigh:=0; 
  LpolW^.Offset:=0; 
  LpolW^.OffsetHigh:=0; 
  LpolW^.hEvent:=Createevent(nil,true,False,nil); 
  Lpolr^.Internal:=0; 
  Lpolr^.InternalHigh:=0; 
  Lpolr^.Offset:=0; 
  Lpolr^.OffsetHigh:=0; 
  Lpolr^.hEvent:=Createevent(nil,true,False,nil);
  PurgeComm(Hcom,Purge_TxAbort or Purge_RxAbort or Purge_Txclear or Purge_Rxclear);
  Post_Event:=Createevent(nil,true,true,nil); 
  //RXComm:=Tcomm.Create(false); 
end;
exports   
      ComInit,WriteStr,ReadStr,FreeMemo,InitMemo;
begin
end.