I need help Guys (Code inside)

[WildGhost]

OOkay, I'm making a DLL (using MASM32). The dll simpley displays a message box.. pretty simple.. I used it from VB, and it worked fine, displayed the messagebox and everything.. Now this is the problem, I changed the source, I want to be able to pass a string value from VB, and the DLL should show a message box with the string that i sent it.. this is the code that I have right now, but all i get is garbage on the message box, the same garbage, it doesn't change or anything....

So once again this is what I'm trying to do:

Pass a string value like so: TestFunction("BlahBlahBLah")
and i want the dll to give a message box with the text BlahBlahBLah.. get what I"m saying? I hope you do.. please someone help lol...

.386
.model flat,stdcall
option casemap:none

;####################################################
    include \masm32\include\windows.inc
    include \masm32\include\user32.inc
    include \masm32\include\kernel32.inc
    
    includelib \masm32\lib\user32.lib
    includelib \masm32\lib\kernel32.lib
;####################################################




.data
AppName db "MAIN DLL FROM FALCY",0
MainMessage db "Hi, This is the message from TestFunction Procedure",0

.data?
MoreMessage LPSTR ?

.code
    DllEntry proc hinstDLL:HINSTANCE,reason:DWORD,reserved1:DWORD
        mov eax,TRUE
        ret
    DllEntry Endp


    TestFunction proc BlahString:LPSTR
        push BlahString
        pop eax
        mov MoreMessage,eax
        push MB_OK
        push offset AppName
        push offset MoreMessage
        push 0
        Call MessageBox
        ret
    TestFunction endp

    End DllEntry

[Jimbob42]

2 things
from VB you need to go ByVal("blah") or SADD("blah") or something like that
also, in the dll you say

push offset MoreMessage

when you mean

push MoreMessage

or even simpler you could go

push MB_OK
push offset AppName
push BlahString
push 0
Call MessageBox

remember that you are getting the offset of the string already

[Zaei]

Another thing to think about is that VB strings are UNICODE, which means that each character is 2 bytes long, instead of the normal 1 byte. They also have a header in front of the string data istelf, to give information about the length of the string. I dont remember exactly how long the header is though.

Z.