[FASM] Error: Symbol already defined

[Yegg]

I started really studying x86 asm recently and decided I would use FASM. I tried writing a basic console hello world application. I'll start by showing my code:

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format PE console
entry start

include 'include\win32ax.inc'

section '.code' code readable executable
  start:
        invoke AllocConsole
        invoke GetStdHandle, STD_OUTPUT_HANDLE
        mov [_outhandle], eax
        invoke GetStdHandle, STD_INPUT_HANDLE
        mov [_inhandle], eax
        invoke WriteConsole, [_outhandle], _msg, 13, _written, 0
        invoke ReadConsole, [_inhandle], _char, 1, _read, 0
  finish:
        invoke ExitProcess, 0

section '.data' data readable writeable
  _outhandle    dd   ?
  _inhandle     dd   ?
  _written      dd   ?
  _read         dd   ?
  _char         db   ?
  _msg          db   'Hello, world.'

section 'idata' import data readable writeable
  library kernel, 'KERNEL32.DLL'

  import kernel,\
         AllocConsole, 'AllocConsole',\
         GetStdHandle, 'GetStdHandle',\
         WriteConsole, 'WriteConsoleA',\
         ReadConsole, 'ReadConsoleA',\
         ExitProcess, 'ExitProcess'

What happens is when I try to assemble this code, I get the following error message:

Error: symbol already defined.

It tells me that the error occured on the following instruction:

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WriteConsole dd RVA _label?000067F

First off, I really don't know what the above (the last text in the code tags) means. When the error dialog shows up, the following code is highlighted:

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import kernel,\
         AllocConsole, 'AllocConsole',\
         GetStdHandle, 'GetStdHandle',\
         WriteConsole, 'WriteConsoleA',\
         ReadConsole, 'ReadConsoleA',\
         ExitProcess, 'ExitProcess'

The above code is apparently the source of the error, located inside my program's source code (hello_world.asm). However, there are two sources of error. My source code (hello_world.asm) and import32.inc. The line of import32.inc which contains the source of error is line 45 which contains the following code:

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label dd RVA _label

I'm not entirely sure if the above is necessary for you to know or not.

Anyways, I'm not really sure what causes this error. If I decide not to define WriteConsole, I get the same type of error message only for ReadConsole instead. If I remove the definition for ReadConsole, it tells me that WriteConsole (and eventually ReadConsole) is not defined.

I would greatly appreciate help with this issue. I'd be glad to provide more information if that is necessary.

Update: I changed a few things. The program now can be compiled into a normal executable, however it will not run so it seems. The few things I changed were:

I changed

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include 'include\win32ax.inc'
to

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include 'include\win32a.inc'
I don't think this had any real effect.

I noticed a small problem where I wrote

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section 'idata' import data readable writeable
I left out the period (.) after the first apostrophe in 'idata'. This was changed into '.idata'.

I changed the import data section's code to:

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section '.idata' import data readable writeable
  library kernel, 'KERNEL32.DLL'

  include 'include\api\kernel32.inc'

This seems to be the main cause for removing the error messages I was receiving earlier. I am still at work trying to get the application to output text to the console. I'll keep this post updated, and I'm still looking for any possible help.

[Kp]

Now that you have it assembled and presumably runnable, run it under a debugger to find out what happens when it calls WriteConsole.

[Yegg]

Now that you have it assembled and presumably runnable, run it under a debugger to find out what happens when it calls WriteConsole.

Thanks for the help. I was getting ready to go ahead and try this, however I started to try and figure out another problem I was working on. The next day I assembled this same code and the program worked just fine. I'm still unsure of what caused it to fail the first time.