How to know the next temp file to be created in windows?

Question

I am by no means a programmer but currently am wondering if an application creates a temp file that windows names. For example the file it creates is tmp001, is there a way i can take that name tmp001 and ask windows to give me the next temp file it would create before it creates it.

Thanks,

Mike

Answer 1

Typically applications use the Win32 API GetTempFileName to get the temporary directory. The process of how the temp file is generated is described there.

I'm not sure why you want this info, but perhaps you could for example register for directory changes via a Win32 API like ReadDirectoryChangesW or by using a mini filter driver.

Answer 2

You would need to define a "temp file" much more explicitly in order to answer this question with a "Yes". The problem is that a "temp file" is just something not meant to be kept. It could exist anywhere on the system and be created by a user, application, or service. This would make it nearly (or actually) impossible to answer your question with a "Yes".

If you constrain the definition of a temp file to just the files in the official temp folder (or a subfolder), you still have a problem if you're trying to catch names not generated by windows. Any app could produce a particularly named temp file in that folder, without Windows caring.

If you further constrain the definition to be only those files named by Windows, you might be able to get somewhere. But, does that really meet your needs?

After all of that, maybe it would be better to describe the problem you're trying to solve. There may be a much better (workable) solution that would address the issue.

Answer 3

There is no direct means to get to know the next temporary filename to be created.

For example, programmers use the System.IO.Path.GetTempFileName method, but one can add application-specific prefixes or suffixes in order to make it easier for the application to find its newly created files.

One can even choose to save this temporary file elsewhere than the system Temp folder.

Answer 4

This kind of code just cannot work reliably on a multi-tasking operating system. Another thread in another process might pre-empt yours and claim the file name you are hoping to create.

This is otherwise easy enough to work around, just name your own files instead of relying on Windows doing it for you. Do so in the AppData folder so you'll minimize the risk of another process messing it up.