<div>
Hi,<br />
<br />
i want to call an activex control from my dll code but when i use the interface of activex control in my dll then it says <br />
&quot;undeclared identifier&quot;.<br />
i know my dll code doesn't find the declaration of interface's pointer.<br />
can you please tell me which header files or libraries i have to include so that i can get the pointer of my activex control.
</div>


Hi,

i want to call an activex control from my dll code but when i use the interface of activex control in my dll then it says
"undeclared identifier".
i know my dll code doesn't find the declaration of interface's pointer.
can you please tell me which header files or libraries i have to include so that i can get the pointer of my activex control.

<div>
<div class="content wysiwyg-content">
Hello,<br />
<br />
I am making a C program which should use an ActiveX control.<br />
<br />
I have an ActiveX control and i know its CLSID, I want to use it so I do :<br />
<br />
hr = CoInitializeEx ( NULL, COINIT_MULTITHREADED );<br />
<br />
then<br />
<br />
hr = CoCreateInstance ( &amp;clsid, <br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;NULL, <br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CLSCTX_INPROC_SERVER, <br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&amp;IID_IUnknown, //(REFIID) &amp;giid, <br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&amp;ppv );<br />
<br />
If I do so ... I have a link error LNK2001 telling me : unresolved external symbol IID_IUnknown<br />
<br />
When I am using an ActiveX control is it a proper manner user IID_IUnknown as the REFIID, if not what should i use as the REFIID and how do I define it.<br />
<br />
<br />

</div>
</div>


Hello,

I am making a C program which should use an ActiveX control.

I have an ActiveX control and i know its CLSID, I want to use it so I do :

hr = CoInitializeEx ( NULL, COINIT_MULTITHREADED );

then

hr = CoCreateInstance ( &clsid, 
		NULL, 
		CLSCTX_INPROC_SERVER, 
		&IID_IUnknown, //(REFIID) &giid, 
		&ppv );

If I do so ... I have a link error LNK2001 telling me : unresolved external symbol IID_IUnknown

When I am using an ActiveX control is it a proper manner user IID_IUnknown as the REFIID, if not what should i use as the REFIID and how do I define it.




Instanciating an ActiveX control into a C program

C is a general-purpose, imperative computer programming language, supporting structured programming, lexical variable scope and recursion, while a static type system prevents many unintended operations. By design, C provides constructs that map efficiently to typical machine instructions, so it has found lasting use in applications that had formerly been coded in assembly language, including operating systems as well as various application software for computers ranging from supercomputers to embedded systems. It is distinct from C++ (which has its roots in C) and C#, and many later languages have borrowed directly or indirectly from C.