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Index > Windows > where dose getchar return to?

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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4624
Location: Argentina
LocoDelAssembly 27 Sep 2010, 16:21
FindAtom:
Code:
.text:7C830D06 ; ATOM __stdcall FindAtomA(LPCSTR lpString)
.text:7C830D06                 public _FindAtomA@4
.text:7C830D06 _FindAtomA@4    proc near
.text:7C830D06
.text:7C830D06 lpString        = dword ptr  8
.text:7C830D06
.text:7C830D06                 mov     edi, edi
.text:7C830D08                 push    ebp
.text:7C830D09                 mov     ebp, esp
.text:7C830D0B                 push    [ebp+lpString]
.text:7C830D0E                 push    0
.text:7C830D10                 push    1
.text:7C830D12                 call    _InternalFindAtom@12 ; InternalFindAtom(x,x,x)
.text:7C830D17                 pop     ebp
.text:7C830D18                 retn    4
.text:7C830D18 _FindAtomA@4    endp
And when InternalFindAtom is about to return:
Code:
.text:7C830C77 loc_7C830C77:                           ; CODE XREF: InternalFindAtom(x,x,x)+121j
.text:7C830C77                 mov     [ebp+var_20], eax
.text:7C830C7A                 cmp     eax, ebx
.text:7C830C7C                 jl      short loc_7C830CC6
.text:7C830C7E
.text:7C830C7E loc_7C830C7E:                           ; CODE XREF: InternalFindAtom(x,x,x)+F4j
.text:7C830C7E                                         ; InternalFindAtom(x,x,x)+9CB5j
.text:7C830C7E                 or      [ebp+ms_exc.disabled], 0FFFFFFFFh
.text:7C830C82                 call    sub_7C830CB5
.text:7C830C87                 mov     ax, word ptr [ebp+var_1C] ; <<<<<<<<<< RETURN VALUE SET HERE. EAX PRE-STATE UNKNOWN
.text:7C830C8B
.text:7C830C8B loc_7C830C8B:                           ; CODE XREF: InternalFindAtom(x,x,x)+9C56j
.text:7C830C8B                                         ; InternalFindAtom(x,x,x)+9CA9j
.text:7C830C8B                 call    __SEH_epilog
.text:7C830C90                 retn    0Ch
.text:7C830C90 _InternalFindAtom@12 endp
Post 27 Sep 2010, 16:21
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20621
Location: In your JS exploiting you and your system
revolution 27 Sep 2010, 23:38
So from that we should always make sure to check the return type and use movsx and movzx as appropriate. Thanks for pointing that out.

So how about boolean return values? I always just check eax against zero. Should I be checking al against zero instead?
Post 27 Sep 2010, 23:38
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4624
Location: Argentina
LocoDelAssembly 28 Sep 2010, 01:16
Best to check here. If by boolean you mean BOOL, then you are correct already. It is worth noting that the documentation defines the "true" value as TRUE and not non-zero, so watch out what you are passing as arguments and the returns values in your callbacks! Razz
Post 28 Sep 2010, 01:16
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20621
Location: In your JS exploiting you and your system
revolution 28 Sep 2010, 01:32
Oh, bool and boolean are different! I had never noticed that before. C is so confusing.
Post 28 Sep 2010, 01:32
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bitshifter



Joined: 04 Dec 2007
Posts: 796
Location: Massachusetts, USA
bitshifter 28 Sep 2010, 07:38
BOOL (as in Win32) is type: signed int
bool (as in C++) is type: unsigned char
Post 28 Sep 2010, 07:38
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guignol



Joined: 06 Dec 2008
Posts: 763
guignol 28 Sep 2010, 12:27
LocoDelAssembly
Very nice, of course, but I kinda meant the function operating on characters/strings & returning character.

P.S. Btw, don't forget that ATOM is a WORD, not int; that is precisely short int.
Post 28 Sep 2010, 12:27
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4624
Location: Argentina
LocoDelAssembly 28 Sep 2010, 17:16
Quote:

that is precisely short int.
unsigned short int actually.

As for functions in MSVCRT or even in the WinAPI returning char, I don't remember any, it seems all of them are defined to either return a char pointer or an int.
Post 28 Sep 2010, 17:16
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guignol



Joined: 06 Dec 2008
Posts: 763
guignol 29 Sep 2010, 16:15
LocoDelAssembly wrote:
As for functions in MSVCRT, or even in [the] WinAPI, dealing with character(s) [...], it seems all of them are defined to either return a [char] pointer or an int.
...which are both 32 bits.
Good.


P.S. Now, be a good boy and stop MHajduking from now on.
You know, with all that "secret" knowledge, topic change, and banal jumble.
Post 29 Sep 2010, 16:15
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MHajduk



Joined: 30 Mar 2006
Posts: 6115
Location: Poland
MHajduk 29 Sep 2010, 16:19
guignol wrote:
P.S. Now, be a good boy and stop MHajduking from now on.
You know, with all that "secret" knowledge, topic change, and banal jumble.
Actually, it's characteristic for you, and rather should be called guignolling.
Post 29 Sep 2010, 16:19
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Fanael



Joined: 03 Jul 2009
Posts: 168
Fanael 29 Sep 2010, 20:16
guignol wrote:
LocoDelAssembly wrote:
As for functions in MSVCRT, or even in [the] WinAPI, dealing with character(s) [...], it seems all of them are defined to either return a [char] pointer or an int.
...which are both 32 bits.
Good.
Untrue.
Post 29 Sep 2010, 20:16
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guignol



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Posts: 763
guignol 30 Sep 2010, 12:18
Fanael wrote:
Untrue.
Eh?
Post 30 Sep 2010, 12:18
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Fanael



Joined: 03 Jul 2009
Posts: 168
Fanael 30 Sep 2010, 21:37
guignol wrote:
Fanael wrote:
Untrue.
Eh?
You know, there's a thing called Win64, where pointers aren't 32 bits anymore.
Post 30 Sep 2010, 21:37
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guignol



Joined: 06 Dec 2008
Posts: 763
guignol 01 Oct 2010, 07:04
You know, you shan't think, falafel - it doesn't suit you.


P.S. MHajduk you are indeed contagious. Rolling Eyes
Post 01 Oct 2010, 07:04
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MHajduk



Joined: 30 Mar 2006
Posts: 6115
Location: Poland
MHajduk 01 Oct 2010, 07:44
guignol wrote:
P.S. MHajduk you are indeed contagious. Rolling Eyes
guignol, I don't know why but I like you anyway. Is it some kind of masochism? I don't know, maybe I just like all the people with an IQ much higher than average (but beware, don't cross the thin red line - you're only fragile wooden Lyonnaise marionette in fact Razz ).
Post 01 Oct 2010, 07:44
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Fanael



Joined: 03 Jul 2009
Posts: 168
Fanael 01 Oct 2010, 11:46
guignol wrote:
You know, you shan't think, falafel - it doesn't suit you.
Who (what?) are you talking about? Razz
Post 01 Oct 2010, 11:46
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