Windows CreateFile Possible Error Codes

Question

I'm playing around with abstracting Windows, Linux, and Mac File IO calls into macros (to avoid C runtime, so no fopen, fclose, etc...). I've actually got quite a bit working but I've run into a stumbling block.

I'm trying to boil down all of the possible errors that could be thrown by each of these platforms into a subset of common ones: Not Found, Exists, Invalid Access, etc.

Linux is obviously well document, Mac even has the most common ones, but Windows does not specify which errors are thrown for its native File I/O functions. We obviously need to use GetLastError(), but I could not find a reference to what the possible values would be.

How about this?

I'm writing a Windows application and using the CreatFile() API. I'd like to handle any errors as gracefully as I can, and perhaps recover from said error instead of telling the user "Crap! Can't do that." But the MSDN docs don't list the possible error codes that could be generated.

Does anyone have a reference to the possible error codes that Windows File functions may generate, specifically (for now) CreateFile()?

Answer 1

Windows supports installable file systems. Microsoft cannot possibly predict what kind of errors a 3rd party file system driver is going to generate so does not make any attempt to promise a strict sub-set of possible error codes.

So yes, you really do have to use GetLastError(). The FormatMessage() function is available to generate a readable string for the error code. In general, the user will get a decent error message that helps him diagnose the root cause. It isn't quite specific enough to tell that an earthquake in Chile severed an undersea communication cable but it will certainly help him to start looking at networking problems for example. You can use the CRT wrappers as well, but with the inevitable loss of specificity. That might be a service call that you have to handle instead of the user's IT staff.

Answer 2

to avoid C runtime

You're reinventing the wheel. C runtime was created so people could write platform-independent programs that (theorietcally) would compile anywhere, as long as you aren't using something platform-specific. Right now, you're doing the same thing.

I'd advise to stop doing that and either use standard C file function, or cross-platform framework that support several platform. You could use either Boost or Qt 4.

Regarding your question

Does anyone have a reference to the possible error codes that Windows File functions may generate,

WinAPI documentation is available on MSDN and you should read it.
CreateFile
GetLastError
SystemErrorCodes

Does anyone have a reference to the possible error codes that Windows File functions may generate

Because CreateFile doesn't only deal with "files" (it also works with directories, pipes, physical devices, etc), you should assume that it can generate any operating system code that exists. According to msdn, there are 16000 codes total. Moral of the story: if you want to generate human-readable message, use FormatMessage. If documentation doesn't list possible error codes (for CreateFile), it automatically means, that CreateFile can produce any error code that exists.