I have created a DLL with the following header:
FirstEntry PROC AllFour:PTR DWord
where the pointer AllFour points to a DWord array.
Now I want to get size of the array pointed to by AllFour in bytes. I have tried several things (mov eax,AllFour and mov eax,OFFSET AllFour), but I can't get the size of the buffer.
Thanks for any help with finding the size of the array pointed to by AllFour.
Welcome!!
How you declare the size of array?
Hi,
Welcome to the forum :icon14:
As HSE already asked: Is it declared somewhere? If yes, pass lengthof:include \masm32\include\masm32rt.inc
.data
MyArray dd 25, 18, 23, 17, 9, 2, 6
.code
FirstEntry PROC ArrLen:DWORD, AllFour:PTR DWord
inkey str$(ArrLen), " elements", 13, 10
ret
FirstEntry endp
start:
invoke FirstEntry, lengthof MyArray, offset MyArray
exit
end start
If you don't know the size, but you are sure that there is a delimiter, e.g. zero, make a loop and check it...
Sometimes libraries provide macros to get the size of the array, e.g. MyArray(?):
include \masm32\MasmBasic\MasmBasic.inc ; download (http://masm32.com/board/index.php?topic=94.0)
.code
Init
Dim MyArray() As DWORD
For_ ecx=0 To Rand(1000) ; random # elements
mov MyArray(ecx), Rand(12345) ; random elements
Next
push VarPtr(MyArray(0))
call FirstEntry
Exit
FirstEntry PROC AllFour:PTR DWord
Inkey Str$("The array has %i elements", MyArray(?))
ret
FirstEntry endp
EndOfCode
Thanks HSE and jj2007. I solved it by passing the length of the array as the first element. But jj's solution is more elegant so I'll try that. If there is any problem, I will post back. Much appreciated.