How do I trap Windows messages?
https://stackoverflow.com/questions/9204141
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I'm making a program called Pwn16. It allows 16-bit applications to run on 64-bit systems by emulating an Intel 8086/Pentium processor and a DOS/Win3.x/Win98 system. Pwn16 uses a small loader program that detects when Windows gives the "not 16-bit compatible" messages (including the one from CMD) and when it notices said message(s) being summoned, it will close it and instead automatically launch Pwn16. Are there any libraries that will let me "capture" these messages and do something else in place of the errors? I'm making most of this in VB6, so any code that can do this will also help. I have the emulation and GUI down, I just need to get this loader done to finish it. Messages I need to capture:
"The version of this file is not compatible with the version of Windows you're running. Check your computer's system information to see whether you need an x86 (32-bit) or x64 (64-bit) version of the program, and then contact the software publisher."
"Unsupported 16-Bit Application: The program or feature '(file)' cannot start or run due to incompatibility with 64-bit versions of Windows. Please contact the software vendor to ask if a 64-bit Windows compatible version is available."
"This is not a valid Win32 application."
"The (file) application cannot be run in Win32 mode."
Thanks.
La solution
As far as I know, neither Explorer nor cmd.exe check the validity of the executable file in advance. Instead, they call CreateProcess and, if it fails, look at the error code returned.
So, if you hook calls to CreateProcess (or perhaps the underlying native API) you should be able to capture the error code being returned to Explorer/cmd.exe/whatever and do your thing instead.
I don't think capturing the message being presented to the user is going to be helpful. Quite apart from the inefficiency involved in examining every dialog box, and every piece of text written to every console, to see whether it contains the message you're looking for, how would you then identify which file the user was trying to run?
