I am trying to run the following code from: Mastering Assembly Programming


I am receiving the following error: user32.dll, Error illegal instruction

include 'win32a.inc'

format PE GUI
entry _start

section '.text' code readable executable
_start:
push 0
push 0
push title
push message
push 0
call [MessageBox]
call [ExitProcess]

section '.data' data readable writeable
message db 'Hello from FASM!', 0x00
title db 'Hello!', 0x00

section '.idata' import data readable writeable
library kernel, 'kernel32.dll',
user, 'user32.dll'

import kernel,\
ExitProcess, 'ExitProcess'

import user,\
MessageBox, 'MessageBoxA'

Any ideas on why this is an error?

Thanks !

Your code missed something:



Also, it is much easier to use invoke macro-extension provided by FASM:

Hello AsmGuru62 !

Your code works perfect. I made the change to my code but it now reports, Error: write failed.
Any ideas?

Thanks

Windows will lock all executable files that are running.

You need to find the existing task, and close/exit/kill it.

Iron-Man: you should post the code change you did.
Usually, "write failed" happens if your code never calls ExitProcess function.
Basically, the previous version of your EXE is still running, as revolution mentioned.

Thanks revolution, AsmGuru62 !!

All is working now.