hi guys. I'm here just to say that RtlZeroMemory has been overwritting some of my data. Are there any known issues with this macro? ty
What macro was used ?
It's a kernel function, but some C-includes have macro to use memset function instead.
i don't know what macro was used but it cleared some data that i needed available. ty
Hi xandaz,
The RtlZeroMemory macro is not defined in windows.inc Could please post here your code?
winnt.h from Pelles C :
#define RtlZeroMemory(Destination,Length) memset((Destination),0,(Length))
A quick test :
include \masm32\include\masm32rt.inc
.data
mystr db 'This line is truncated.'
mystr2 db 'Test'
.data?
RtlZeroMem MACRO Destination,Length
invoke crt_memset,Destination,0,Length
ENDM
.code
start:
RtlZeroMem ADDR mystr2,4
invoke StdOut,ADDR mystr
invoke ExitProcess,0
END start
include \masm32\include\masm32rt.inc
.data
somestring db "Hello, this is a simple string intended for testing string algos. It has 100 characters without zero", 0
.code
start:
print "["
print offset somestring, "]", 13, 10
invoke RtlZeroMemory, addr somestring, sizeof somestring
print "["
print offset somestring, "]", 13, 10
MsgBox 0, "Surprise, surprise, it works!!", "RtlZeroMemory, an old Kernel32 function:", MB_OK
exit
end start
Under the hood:
0040101F |. 6A 65 push 65 ; /Arg2 = 65
00401021 |. 68 00204000 push offset 00402000 ; |Arg1 = ASCII "Hello, this is a simple string intended for testing string algos. It has 100 characters without zero"
00401026 |. E8 ED000000 call <jmp.&kernel32.RtlZeroMemory> ; \ntdll.RtlZeroMemory
Hi Jochen,
I get this error message :
error LNK2001: unresolved external symbol _RtlZeroMemory@8
Quote from: Vortex on October 27, 2021, 06:19:27 AM
Hi Jochen,
I get this error message :
error LNK2001: unresolved external symbol _RtlZeroMemory@8
Hi Erol,
For such cases, I always have a virgin Masm32 SDK on C:\Masm32. Attached exe assembled with qEditor "build all" :cool:
You could alway look at the library module "memfill" but a fill algo is very simple to write. I have always wondered why people chase after a C runtime function when the actual algo is so simple.
True, Hutch, but RtlZeroMemory is not a C runtime function but a Kernel32/NtDll function.
That makes sense, I have used it so rarely that I was not sure where it came from.
Hi Jochen,
Thanks, you are right. I fixed the problem in my Masm32 installation.