vb-c++-connection

AMK's Avatar, Join Date: Sep 2006
AMK
Newbie Member
c++ dll has exported funtion call such as:
void AccessUnknownBuf(char** cbuffer, int sizeofbuf);
VB does not know about the size of cbuffer beforehand. It has to get the cbuffer and its size from dll. How VB can do this?. somehow it should be accessing dll's memory area...?. seconldy, how to allocate more than 40000 bytes for character string type?.
dim s as string*50000 does not work.
AMK's Avatar, Join Date: Sep 2006
AMK
Newbie Member
It is actually like this:
void AccessUnknownBuf(char** cbuffer, int* sizeofcbuffer);
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
AccessUnknownBuf should supply the size of the buffer for some default parameter and in VB use the string with SPACE to fill the buffer and pass that as an argument to the function.
AMK's Avatar, Join Date: Sep 2006
AMK
Newbie Member
how do you allocate this many mem space to string?.
Dim s as string*50000 (got overflow error).
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Code:
Dim str As String
str = Space(1000)
This will allocate the string with 1000 buffer size by default and this can be used easily with the C++ buffer.
AMK's Avatar, Join Date: Sep 2006
AMK
Newbie Member
there is no way that i can access c++ dll's cBuffer content without allocating memory in VB?.
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
I dont think so. You are calling a function in a C++ dll and all you can get is the return type of the function or any pointer that you provide are having some data and the second option requires you to have the buffer in VB and pass that to C++ dll.