Message Box example

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shaolin007

Joined: 03 Sep 2004
Posts: 65

shaolin007 24 May 2005, 19:36

I guess I don't quite get it yet but I'm having trouble doing a simple MessageBox with FASM and going by Izcelion Windows MessageBox tutorial. Could someone show me an example of a MessageBox using NO-MACROS please? Thanks...

24 May 2005, 19:36

Torrey

Joined: 12 Oct 2003
Posts: 78

Torrey 24 May 2005, 19:50

Here you go.

Code:

format PE GUI 4.0
entry BeginCode

include '%fasminc%\win32a.inc'

section '.code' executable readable writeable

BeginCode:
        push 0
        push txtTitle
        push txtMessage
        push 0
        call [MessageBox]

        ;or alternate way of calling api's or procs
        invoke MessageBox,0,txtMessage,txtTitle,0
        invoke ExitProcess,0
        ret

section '.data' data readable writeable

txtTitle        db      'Titlebar',0
txtMessage      db      'Hello World',0

section '.idata' import data readable writeable

  library kernel,'KERNEL32.DLL',\
          user,'USER32.DLL'

  import kernel,\
         ExitProcess,'ExitProcess'

  import user,\
         MessageBox,'MessageBoxA'

Last edited by Torrey on 24 May 2005, 19:58; edited 1 time in total

24 May 2005, 19:50

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland

Tomasz Grysztar 24 May 2005, 19:53

Or just the PEDEMO example in the fasm for Windows package. No macros at all (actually it's the oldest program for Win32 ever written in fasm).

24 May 2005, 19:53

shaolin007

Joined: 03 Sep 2004
Posts: 65

shaolin007 24 May 2005, 20:12

Ok could you help me out with this part of PEDEMO and what exactly is going on? Thanks man...

Code:

section '.idata' import data readable writeable

  dd 0,0,0,RVA kernel_name,RVA kernel_table
  dd 0,0,0,RVA user_name,RVA user_table
  dd 0,0,0,0,0

  kernel_table:
    ExitProcess dd RVA _ExitProcess
    dd 0
  user_table:
    MessageBox dd RVA _MessageBoxA
    dd 0

  kernel_name db 'KERNEL32.DLL',0
  user_name db 'USER32.DLL',0

  _ExitProcess dw 0
    db 'ExitProcess',0
  _MessageBoxA dw 0
    db 'MessageBoxA',0

24 May 2005, 20:12

shaolin007

Joined: 03 Sep 2004
Posts: 65

shaolin007 24 May 2005, 20:14

I'm having trouble getting this to work in your program

Code:

include '%fasminc%\win32a.inc' 

my directory is

include 'C:\fasm\include\win32a.inc'

Do the '%%' mean anything special?

24 May 2005, 20:14

flaith

Joined: 07 Feb 2005
Posts: 122
Location: $300:20 58 FC 60 N 300G => Vietnam

flaith 24 May 2005, 21:02

check your FASMW.INI and change lines inside it :

Quote:

[Compiler]
Memory=16384
Priority=0
[Options]
SecureSelection=0
AutoBrackets=0
AutoIndent=1
SmartTabs=1
OptimalFill=1
ConsoleCaret=1
[Colors]
Text=0,0,0
Background=255,255,255
SelectionText=255,255,255
SelectionBackground=10,36,106
Symbols=48,48,240
Numbers=0,144,0
Strings=176,0,0
Comments=128,128,128
[Font]
Face=Courier New
Height=-13
Width=0
Weight=400
Italic=0
CharSet=0
[Window]
Top=276
Left=515
Right=899
Bottom=600
Maximized=0
[Help]
Path=F:\Documents and Settings\Administrateur\Bureau\ASM\FASMHelp.chm
[Environment]
Fasminc = G:\DEV\FASM\WINDOWS\INCLUDE
Include = G:\DEV\FASM\WINDOWS\INCLUDE

last two lines

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24 May 2005, 21:02

coconut

Joined: 02 Apr 2004
Posts: 326
Location: US

coconut 24 May 2005, 21:07

in order to eliminate the use of a hard coded path to include files, you can create an environment variable named FASMINC, and use that when pointing to your includes..

on win2000\xp right click my computer goto advanced, click the Environment Variables button at the bottom, and create a variable in the top listbox.. name it FASMINC and set the value to your include folder - no trailing backslash

by setting FASMINC to your "c:\asm\alot\of\folders\fasm\include"
you can use the %fasminc% and make it easier for yourself and to share your code among others

note: your can use the following resource section in your code, instead of manually importing every api you use, fasm will only generate import code for the api you actually use

Code:

section '.idata' import data readable writeable

  library kernel32,'KERNEL32.DLL',\
          user32,'USER32.DLL'

  include 'apia\kernel32.inc'
  include 'apia\user32.inc'

if you use an api from other DLLs, simply add it here

24 May 2005, 21:07

shaolin007

Joined: 03 Sep 2004
Posts: 65

shaolin007 25 May 2005, 00:53

Hey thanks everyone that helped out! I finally got it to work correctly. Thanks for helping out a Windows Newbie. Smile

One last questions, why do you do this?

Code:


call [MessageBox]

instead of 

call MessageBox

I take its an address in the .dll?

25 May 2005, 00:53

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 25 May 2005, 06:58

MessageBox is not a procedure label, but simply DWORD, where Windows puts actual address of MessageBox from user32.dll. This happens during loading of the PE exe file and this is the essense of so called "importing functions from dynamic linkable library (dll)).
This is the reason why imported functions should be called using indirect addressing [MessageBox].
See also the macro "invoke", intended to call imported functions.

Regards.

25 May 2005, 06:58

Nikolay Petrov

Joined: 22 Apr 2004
Posts: 101
Location: Bulgaria

Nikolay Petrov 25 May 2005, 19:33

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25 May 2005, 19:33

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