What algorithm does the Windows Run Dialog use?

Question

I have a set of files (".r2w") extensions, that have a file association with Attachmate Reflection. I have several of these in a folder, which I've added to the PATH. I've also added .r2w to PATHEXT.

This setup appears to be correct for cmd.exe, but does not work from the Run dialog (Win+R). For example, I have one file 'test.r2w'. From cmd.exe, I can simply type "test" and it launches correct. However, typing "test" in Run dialog does not work.

I ran Process Monitor, and it appears that the algorithm for command searching for the Run dialog is different than what is the "The PATH Command and PATHEXT Variable" section here: http://technet.microsoft.com/en-us/library/cc723564.aspx

1) Can anyone explain what the command search algorithm is for the Run Dialog?

2) Can anyone provide a way to set up the Run Dialog to do what I want - specifically be able to run .r2w files without having to type the extension?

Answer 1

Well, the run dialog != the NT command interpretter.

But my guess is that it uses the same algorithm as ShellExecuteEx. I remember an Old New Thing blog post that shows how you could mimic some of the functionality of the Run Dialog box's search by calling the ShellExecute command.

If I was Microsoft, I wouldn't document the search algorithm either. It's an implementation detail.