To do a second development of software, the manufacturer provides a COM type of DLL library,
My way is:
1. The way of c + + builder to import the type library to generate xx_LIB. CPP and xx_LIB. J h,
2. The generated files added to the above project and # include xx_LIB. H
3. Then create an instance according to online and call a function, the code is as follows:

 void __fastcall TForm1: : Button1Click (TObject * Sender)//initialize the COM object and create an 
{
Retrieves the init. 
Retrieves the hr; 

Init=CoInitialize (NULL);//initialize the COM libraries 
If (SUCCEEDED (init)) 
{
ShowMessage (" initialize COM object success "); 
} 

//-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
IRenishawDX10 * pDX10=NULL;//create an object 
Hr=CoCreateInstance (Dx10sdkadaptorlib_tlb: : CLSID_DX10Adaptor, NULL, CLSCTX_INPROC_SERVER, Dx10sdkadaptorlib_tlb: : IID_IRenishawDX10, (void * *) & amp; PDX10); 
If (SUCCEEDED (hr)) 
{
BSTR bstrSerNum=0; 
VARIANT_BOOL bOK. 

PDX10 - & gt; AddRef (); 
Edit1 - & gt; Text="create COM objects success"; 
PDX10 - & gt; The Connect (& amp; BstrSerNum, & amp; BOK);//connection 
PDX10 - & gt; Release (); 
} 
//-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

CoUninitialize ();//terminate the COM library 

} 

But the problem is to run to the calling function namely pDX10 - & gt; The Connect (& amp; BstrSerNum, & amp; BOK); This row is memory error:

Access violation at 0 x7725fad5: write of address 0 x00030e70

CodePudding user response:

When calling a function parameter error?

CodePudding user response:

Check whether the variable type

CodePudding user response:

Recent OPC, also for COM headache, encountered a similar problem, I bring somebody else vs generated DLL BCB, can in the operation of the call is not normal

CodePudding user response:

BSTR bstrSerNum=0; Don't allocate space