请教:VB调用VC dll 报错
VC中的导出的函数是这样的:
extern "C" __declspec(dllexport)
HRESULT Connect(LPCSTR IpAddr, CHAR* pcUserName = NULL, CHAR* pcPassword = NULL)//返回0表示连接成功,非0则失败
{
...
}
我在VB中声明如下:
Declare Function Connect Lib "C:\example.dll" (ByVal IpAddr As String, ByVal UserName As String, ByVal Passwd As String) As Integer
同时,我定义
Const NULL = 0
然后调用:
Dim result As Integer
result = Connect("138.139.0.230", NULL, NULL)
If result <> 0 Then
MsgBox("error_connect")
Return
End If
结果总是报错,请问哪里不对呢?