Windows filename - How to check if filename would be valid?

Question

I wanted a function, possibly amongst Path Functions, that would check if file-name would be valid. By valid, I meant if character present in the string are all valid (having no ?, > etc, for example). But sadly, there is no function. Browsing through the net, and SO, I found few techniques, none of them I liked, or found solid.

• Using a regular expression to check the contents of filename.
• Creating a file name, possibly in %TEMP% path of the system. If creation fails, the filename is (possibly) invalid. Otherwise, it is valid (and therefore, delete the file).
• Write up a function, that checks if invalid characters are present in the filename (e.g. ?:*>)

An extended form of function would be to check all invalid names (like AUX, CON etc), but that's not an issue (at least for now).

Is there any documented/undocumented function, that I might have missed, which would reliably check if filename (not pathname) is valid.

Answer 1

Edit: the PathCleanupSpec function is now deprecated and no longer supported. Refer to the Requirements section at the end of the linked page for details.

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Thanks Connor, for the function. For other readers, the function name is PathCleanupSpec. Using which I have implemented following:

bool IsLegalFileName(LPCWSTR filename)
{
    WCHAR valid_invalid[MAX_PATH];
    wcscpy_s(valid_invalid, filename);

    int result = PathCleanupSpec(nullptr, valid_invalid);

    // If return value is non-zero, or if 'valid_invalid' 
    // is modified, file-name is assumed invalid
    return result == 0 && wcsicmp(valid_invalid, filename)==0;
}