Exporting C Functions in a DLL

[MyndFyre]

WOW! New strange problem, if I call this function 2 times i crash! Wtf? Should I set everything to null at the end of the function?

It's not really that strange!  Take a look at your code!  You're declaring s1, but you're never allocating memory.  You're overwriting arbitrary memory.  Very, very scary!  You should definitely allocate memory that you're going to memcpy or strcpy to!

[K]

That is wrong on so many levels.  I would try something like this:

Code Select Expand


int __stdcall get_version (char* out)
{
    const char* version = "1.0.0";
    strcpy( out, version);
    return strlen(version);
}


Code Select Expand


Public Declare Function [Whatever] (ByVal out As String) As Long

Dim buffer As String
Dim len as Long

buffer = Space(255);
len = Whatever(buffer);
buffer = Left(buffer, len);


[FrostWraith]

I'm starting to understand this space thing. So basically what you want to do before you call the get_version function is free up some space that can be over written by the function?  If so, should this standard be used when calling, say, a local VB function?

Also: If the length of the string is static, should I just lower the space to (in this case) 5?

[Kp]

Five is not sufficient.  You're forgetting the terminating null character.

You don't need to preallocate space for calls between functions in VB (as far as I know), but generally you will need to preallocate when calling between different languages.  If you were staying purely in C, you could let the callee allocate it and burden the caller with freeing it.  Strictly speaking, you can do that with VB->C as well, but it's more troublesome.