Enumerating top level windows

[Vortex]

Here is a quick example :

Code Select Expand

include     EnumWnd.inc

.data

f1          db '%s',13,10,0

.data?

buffer      db 128 dup(?)
buffer2     db 128 dup(?)

.code

start:

    invoke  EnumWindows,ADDR EnumWndProc,0
    invoke  ExitProcess,0
   

EnumWndProc PROC hwnd:DWORD,lParam:DWORD

    invoke  GetWindowText,hwnd,ADDR buffer,64
    invoke  wsprintf,ADDR buffer2,ADDR f1,ADDR buffer
    invoke  StdOut,ADDR buffer2
    mov     eax,1
    ret

EnumWndProc ENDP

END start


[TimoVJL]

Empty lines should avoid too.
Also wsprintf give count of chrs to print text, so it can be used too.
WriteFile / WriteConsole works well with wsprintf.

[Vortex]

Hi Timo,

Thanks, I will take care of it.

[Vortex]

Hi Timo,

Here is the new version skipping the blank lines :

Code Select Expand

include     EnumWnd.inc

.data

f1          db '%s',13,10,0

.data?

buffer      db 128 dup(?)
buffer2     db 128 dup(?)

.code

start:

    invoke  EnumWindows,ADDR EnumWndProc,0
    invoke  ExitProcess,0
   

EnumWndProc PROC hwnd:DWORD,lParam:DWORD

    invoke  GetWindowText,hwnd,ADDR buffer,64
    invoke  wsprintf,ADDR buffer2,ADDR f1,ADDR buffer
    cmp     eax,2
    je      @f
    invoke  StdOut,ADDR buffer2
@@:
    mov     eax,1
    ret

EnumWndProc ENDP

END start


[TimoVJL]

I was after something like this

Code Select Expand

include     EnumWnd.inc
includelib user32.lib

STD_OUTPUT_HANDLE equ -11

GetStdHandle PROTO :DWORD
WriteFile PROTO :DWORD,:DWORD,:DWORD,:DWORD,:DWORD

.data

f1          db '%s',13,10,0

.data?

hStdOut dd ?
buffer      db 128 dup(?)
buffer2     db 128 dup(?)

.code

start:
    invoke  GetStdHandle, STD_OUTPUT_HANDLE
    mov     hStdOut, eax
    invoke  EnumWindows,ADDR EnumWndProc,0
    invoke  ExitProcess,0
   

EnumWndProc PROC hwnd:DWORD,lParam:DWORD
    invoke  GetWindowText,hwnd,ADDR buffer,64
    invoke  wsprintf,ADDR buffer2,ADDR f1,ADDR buffer
    cmp     eax,2
    je      @f
invoke  WriteFile, hStdOut, ADDR buffer2, eax, 0, 0
@@:
    mov     eax,1
    ret

EnumWndProc ENDP

END start


[Vortex]

Hi Timo,

Here is the new version eliminating the extra branching :

Code Select Expand

include     EnumWnd.inc

.data

f1          db '%s',13,10,0
ZeroVal     dd 0
ZeroPtr     dd OFFSET ZeroVal

.data?

hStdOut dd ?
buffer      db 128 dup(?)
buffer2     db 128 dup(?)

.code

start:

    invoke  GetStdHandle, STD_OUTPUT_HANDLE
    mov     hStdOut,eax
    invoke  EnumWindows,ADDR EnumWndProc,0
    invoke  ExitProcess,0
   

EnumWndProc PROC USES ebx hwnd:DWORD,lParam:DWORD

    mov     ebx,OFFSET buffer2
    invoke  GetWindowText,hwnd,ADDR buffer,64
    invoke  wsprintf,ebx,ADDR f1,ADDR buffer
    cmp     eax,2
    cmovz   ebx,DWORD PTR [ZeroPtr]
    invoke  WriteFile,hStdOut,ebx,eax,0,0
    mov     eax,1
    ret

EnumWndProc ENDP

END start


[TimoVJL]

More fun, eliminate wsprintf and buffer2

Code Select Expand

    invoke  GetWindowText,hwnd,ADDR buffer,64
    cmp     eax,0
    je      @f
    mov     WORD PTR[buffer+eax], 0A0Dh
    add     eax, 2
    invoke  WriteFile, hStdOut, ADDR buffer, eax, 0, 0
@@:


[John Z]

A fun fact - the maximum 'displayable' text in the title bar is 255 characters so while that length would be unusual just 64 characters might only be 1/4th of the text.  Also the text can be much longer than 255 but only 255 are displayed.


John Z

[Vortex]

Reading Timo's and John's messages, here is the new version :

Code Select Expand

include    EnumWnd.inc

.data

ZeroVal    dd 0
ZeroPtr    dd OFFSET ZeroVal
msg        db '%s',13,10,0

.data?

buffer      db 256 dup(?)
buffer2    db 256 dup(?)

.code

start:

    invoke  EnumWindows,ADDR EnumWndProc,0
    invoke  ExitProcess,0

EnumWndProc PROC hwnd:DWORD,lParam:DWORD

    invoke  GetWindowText,hwnd,ADDR buffer,255
    mov    edx,OFFSET msg
    test    eax,eax
    cmovz  edx,DWORD PTR [ZeroPtr]
    invoke  printf,edx,ADDR buffer
    mov    eax,1
    ret

EnumWndProc ENDP

END start