ASM Community

Hi people. Newbie(ish) question.

I've got an EXE file and it compiles fine, but assembling brings up the following error:

Assembling: C:\ASM Stuff\ASM\EXE Export\Export.asm
Microsoft (R) Incremental Linker Version 5.12.8078
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.

LINK : error LNK2001: unresolved external symbol _WinMainCRTStartup
Export.exe : fatal error LNK1120: 1 unresolved externals

Make error(s) occured.

Here's the code:

.486

.model flat, stdcall

option casemap:none



include \masm32\include\windows.inc

include \masm32\include\kernel32.inc

include \masm32\include\user32.inc



includelib \masm32\lib\kernel32.lib

includelib \masm32\lib\user32.lib



;

; Prototypes

;

WinMain proto :DWORD,:DWORD,:DWORD,:DWORD





.data

 szBuffer db 256 dup(0)

 

.code



WinMain proc hInst:HINSTANCE,hPrevInst:HINSTANCE,CmdLine:LPSTR,CmdShow:DWORD



 invoke GetModuleFileName,0,ADDR szBuffer, 256

 OR EAX, EAX

 JZ Finish				  			; Leave if something went wrong

 

 Add EAX, OFFSET szBuffer ; Get a pointer to the buffer string

 

 Dec EAX

 Cmp BYTE PTR [EAX], "\"

 Jne Finish

 

 Mov BYTE PTR [EAX], 0

 

 invoke MessageBox,0,EAX,0,MB_OK

 

Finish: 

 invoke ExitProcess, 0

 

WinMain endp



End

It's just a test file I'm working on using code I found in a post today. Just wondering why I'm getting the linker error. I've checked the FAQ and found nothing. A search on this site brought up one post

http://www.asmcommunity.net/board/index.php?topic=2523&highlight=unresolved+external+symbol+WinMainCRTStartup

but I couldn't see precisely what the answer was to that question.

Cheers.

You are missing "Foo" and "End foo".
Try this:

.486

.model flat, stdcall

option casemap:none



include \masm32\include\windows.inc

include \masm32\include\kernel32.inc

include \masm32\include\user32.inc



includelib \masm32\lib\kernel32.lib

includelib \masm32\lib\user32.lib



;

; Prototypes

;

;WinMain proto :DWORD,:DWORD,:DWORD,:DWORD





.data

 szBuffer db 256 dup(0)

 

.code



foo:

; WinMain proc  hInst:HINSTANCE,hPrevInst:HINSTANCE,CmdLine:LPSTR,CmdShow:DWORD



 invoke GetModuleFileName,0,ADDR szBuffer, 256

 OR EAX, EAX

 JZ Finish				  			; Leave if something went wrong

 

 Add EAX, OFFSET szBuffer ; Get a pointer to the buffer string

 

 Dec EAX

 Cmp BYTE PTR [EAX], "\"

 Jne Finish

 

 Mov BYTE PTR [EAX], 0

 

 invoke MessageBox,0,EAX,0,MB_OK

 

Finish: 

 invoke ExitProcess, 0

 

;WinMain endp



End foo

:tongue: :grin: :)

Most people would use something like start instead of foo, but as you can see, it doesn't matter.

:)

http://www.tuxedo.org/~esr/jargon/html/entry/foo.html

and

http://www.tuxedo.org/~esr/jargon/html/entry/metasyntactic-variable.html

You are talking foo, stryker...

nah...

he just left out the most important thing of a program entry point :grin:

start:

...

...

...

end start

cheers :grin:

oh I see :grin:

usually I just do like this

labelname:

nameoffunction PROC

macroname MACRO

....

still the same but foo is much shorter and saves us a few keystrokes and save us a couple of milliseconds of typing. :grin:

Since I dont use the simplified segments and stuff, I just found is easier to do this:

.686

.MMX



.model flat,stdcall

option casemap:none

option dotname



include \masm32\include\windows.inc

include \masm32\include\kernel32.inc

include \masm32\include\user32.inc

includelib \masm32\lib\kernel32.lib

includelib \masm32\lib\user32.lib



	[COLOR=red]public WinMainCRTStartup[/COLOR]



_TEXT SEGMENT



[COLOR=red]WinMainCRTStartup label dword[/COLOR]

align 4

	invoke GetModuleHandle, NULL

	mov    hInstance,eax

	invoke main,eax,NULL,SW_SHOWDEFAULT

	invoke ExitProcess,eax

.

.

.

For some reason I have had problem even with the start directive, but this works every time.

Not really sure. I don't use start: and end start(?) anymore.