Giving unsigned char** a value in C++ - c++

Question

I'm really rusty with C++ and pointers and can't figure out a solution to my problem.
Here is the context:
I have to write a DLL to replace an old one and for one of the functions i must follow this signature:
int GetText(unsigned char** outBuf, unsigned int* outLen);
In the final piece of software, the value of outBuf is displayed in a textbox.
If i understand correctly, outBuf is a pointer to a pointer, or a pointer to char array.
outLen seems to be the length of the data i provide to this buffer.
To test out this function, i'd like to create from scratch a char array and pass it to outBuf.
What i tried so far:
int GetText(unsigned char** outBuf, unsigned int* outLen){
*outBuf = NULL;
*outLen = 0;
//Create a char array from scratch, just to test...
unsigned char text[] = "Hello";
//outLen is the size of text
*outLen = sizeof(text);
//I allocate size to outBuf
*outBuf = new unsigned char[*outLen];
//I copy value of text into outBuf
memcpy(*outBuf, &text, *outLen);
return OK;
};
Is my code to give value to *outBuf and *outLen correct and what could lead it to not working? Because when i try it with the piece of software i was given to test the dll, it fails. It displays a dialog saying Reading failed with status 0.
The function seems to go through as the return value(status) is taken in account. But it doesn't manage to display anything. As if one of the variables i return is empty or null...
here is an extract from the final software (in VB) calling the function. As i'm not allowed to disclose the real code, i changed some value callings:
'lance la lecture
StatusInt = LectureText(NumText, textStr
If StatusInt = 0 Then
'traitement des sauts de ligne
textStr= Replace(textStr, Chr(&HD) + Chr(&HA), Chr(&HA))
textStr= Replace(textStr, Chr(&HA), Chr(&HD) + Chr(&HA))
'copie dans la textbox
Text1.Text = textStr
Else
MsgBox "Lecture failed with err " & Str(StatusInt)
End If
And the function
Public Function LectureText(ByVal NumText, ByRef Text As String) As Long
Dim AddrText As Long
'Dim TextAs String
Dim LengthText As Long
Dim status As Long
'lecture du text
status = GetText(AddrText, LengthText)
'si lecture ok, copie et lib�re le buffer
If status = 0 And LengthText <> 0 Then
'Alloue l'espace n�cessaire pour le text
Text = String(LengthText, vbNullChar)
'copie du text
CopyMemory ByVal Text, ByVal AddrText, LengthText
End If
'retourne status
LectureText= status
End Function
As you can see, if you provide a status = 0, it should not call the dialog saying there is an error. But in my case, it says "Lecture failed with err 0". How is it even possible...
i'm sure it's not the correct way to make things but i don't usually work with C++ and need to spend as little time as possible on this problem. I already searched for 2 days would need to take many things back from the start about C++. Thing i can't offer now.
Thanks in advance for your kind help

Answer 1

The code i wrote was correct.
The fact is my functions needed to be declared with __stdcall to be compatible with VB.
But when compiling the dll with __stdcall, Visual Studio was adding decoration to function names and the existing software in VB was trying to call them by their undecorated names.
So i added a definition file (.def) to my project so that the function names are exported correctly.