VC动态调用DLL

 

CyTangTP.dll共提供三个函数,此文件拷贝在运行目录下。

在VB环境下声明如下：

在Module1中定义动态库函数；

Declare Function OpenComm Lib "CyTangTP.dll" (ByVal ComNo As Integer, ByVal Baud As Integer) As Long

Declare Function CloseComm Lib "CyTangTP.dll" (ByVal Handle_Of_Com As Long) As Integer

Declare Function SendMsg Lib "CyTangTP.dll" (ByVal Handle_Of_Com As Long, ByVal TPSet  As String, ByVal Msg As String) As Integer

 

现在，我们要在VC中调用这三个函数，实现代码如下：

 

HMODULE module = LoadLibrary("CyTangTP.dll");
    typedef long (CALLBACK* pOpen)(int, int);//注意这里
    typedef long (CALLBACK* pSend)(long,CString,CString);//注意这里
    typedef int (CALLBACK* pClose)(long);//注意这里

    if (module)
    ...{
        //调用OpenComm
        pOpen Open = (pOpen)GetProcAddress(module,"OpenComm");
        long port;
        if(Open!=NULL)
        ...{
            port = Open(1,9600);
            MessageBox("Open");
        }
        else 
            return;

        //调用SendMsg
        pSend Send = (pSend)GetProcAddress(module,"SendMsg");
        int nSend = 1;
        if(Send!=NULL)
        ...{
            nSend = Send(port,"0,20,2,1,1,1,1,0,1","RabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMN12345678901234567890欢迎光临东方信通科技");
            CString str;
            str.Format("%d",nSend);
            MessageBox(str);
        }
        
        //调用CloseComm
        pClose Close = (pClose)GetProcAddress(module,"CloseComm");
        int nClose;
        if(Close!=NULL)
        ...{
            nClose = Close(port);
            CString str;
            str.Format("%d",nClose);
            MessageBox(str);
        }

        FreeLibrary(module);
    }