declaring api functions

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silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 24 Oct 2003, 17:49

Code:

 

format MS COFF

extrn '__imp__MessageBoxA@16' as MessageBox:dword

include '%include%\win32a.inc'

section '.text' code readable executable

 public start 

 start:
        invoke MessageBox, 0 ,_caption , _message , 0      

        ret

section '.data' data readable writeable

 _caption db 'Win32 assembly',0
 _message db 'Coffee time!',0

I would like to know exactly how the extern directive works. All I know is I need it to use the MessageBox function. I am thinking about creating some include files with declarations for all of the functions in user32.dll and kernel32.dll but I want to know if doing this will increase the size of the object file generated even if I don't use all the functions.

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silkodyssey

24 Oct 2003, 17:49

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8351
Location: Kraków, Poland

Tomasz Grysztar 24 Oct 2003, 18:20

It is covered in the FAQ on the main fasm's website.

24 Oct 2003, 18:20

silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 24 Oct 2003, 19:12

Thank you, I'll check it out Smile

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silkodyssey

24 Oct 2003, 19:12

silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 24 Oct 2003, 20:18

I am having a problem with the EXTRN macro. Its giving me this error:

Code:

 
flat assembler  version 1.49
msgbox.asm [11]:
EXTRN '__imp__MessageBoxA@16' as MessageBox:dword
msgbox.asm [6] EXTRN [1]:
     if used symbol
error: invalid expression.

Make error(s) occured.

Here's the code

Code:

 
format MS COFF

 macro EXTRN symbol
    {
     if used symbol
      extrn symbol
     end if
    }

EXTRN '__imp__MessageBoxA@16' as MessageBox:dword

include '%include%\win32a.inc'
;include 'c:\fasm\user32.inc' 

section '.text' code readable executable

 public start 

 start:
        invoke MessageBox, 0 ,_caption , _message , 0      

        ret

section '.data' data readable writeable

 _caption db 'Win32 assembly',0
 _message db 'Coffee time!',0

_________________
silkodyssey

24 Oct 2003, 20:18

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8351
Location: Kraków, Poland

Tomasz Grysztar 24 Oct 2003, 23:58

This macro is designed only for the "EXTRN name" syntax, if you want to use the extended one, try something like:

Code:

macro EXTRN symbol,name
{ if used symbol
    if name eq
      extrn symbol
    else
      extrn name as symbol 
    end if
  end if }

and use it like here:

Code:

EXTRN MessageBox,'MessageBoxA'

24 Oct 2003, 23:58

silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 25 Oct 2003, 01:11

Thanks Privalov it works like a charm, you're a genius Very Happy

. The file size went from 70kb down to 2kb Very Happy

. I can upload some of the includes I've converted from the masm32 package if anyone's interested.

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silkodyssey

25 Oct 2003, 01:11

Vortex

Joined: 17 Jun 2003
Posts: 318

Vortex 25 Oct 2003, 08:41

Sikodyssey,

I have a tool converting masm32 include files to fasm includes:

http://board.win32asmcommunity.net/showthread.php?s=&threadid=8994

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Code it... That's all...

25 Oct 2003, 08:41

silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 25 Oct 2003, 14:04

I checked out your program. Just what I needed. If only I knew about it yesterday Very Happy

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silkodyssey

25 Oct 2003, 14:04

Vortex

Joined: 17 Jun 2003
Posts: 318

Vortex 25 Oct 2003, 20:07

Silkodyssey,

You can try also my "scanner" tool,it looks for API functions in the asm source file and creates a list declaring all the necessary functions.With this tool,you don't have to use API include files.

You can have a look at:

http://board.flatassembler.net/topic.php?t=72

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Code it... That's all...

25 Oct 2003, 20:07

silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 25 Oct 2003, 20:57

This would be a great feature for fasmw. It would be more convient to have the source file scanned from the IDE and the functions declared there instead of having to run an external program. Smile

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silkodyssey

25 Oct 2003, 20:57

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8351
Location: Kraków, Poland

Tomasz Grysztar 25 Oct 2003, 21:00

Maybe it should become the part of FRESH project?

25 Oct 2003, 21:00

Vortex

Joined: 17 Jun 2003
Posts: 318

Vortex 26 Oct 2003, 09:31

Nice idea.The problem is that I haven't much time for coding because of long working hours. Yet,I will think of coding a scanner DLL for the FRESH project.

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26 Oct 2003, 09:31

decard

Joined: 11 Sep 2003
Posts: 1092
Location: Poland

decard 26 Oct 2003, 12:46

Vortex,
Good work with your scan program Smile

.
Unfortunately, it doesn't work with multi-sourcefile projects. Maybe you could add a feature that will also scan files included by the file given in command line?

26 Oct 2003, 12:46

Vortex

Joined: 17 Jun 2003
Posts: 318

Vortex 26 Oct 2003, 18:56

decard wrote:

Maybe you could add a feature that will also scan files included by the file given in command line?

Yes,I was thinking about this idea.It can be a solution for multi-source files.

Thanks,

Vortex

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26 Oct 2003, 18:56

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