John Maddock wrote:
It seems that testing for a path "J:/foo/bar" on a Win98 or Win2000 machine (unsure which ATM) that doesn't have a J: drive is returning true falsely here because you ain't catching the correct error. Now, I have to say I don't agree with this policy of JM's, but suspect that the actual error is ERROR_INVALID_DRIVE. Will get back to you when my testers get back to me.
I'm not sure I agree with that policy either: that's why there's a comment in the code that it may not be correct. The basic problem is we don't know which error codes represent "file does not exist", as opposed to some other error. The fact there is no documentation on which error codes that API can return makes the problem particularly tricky :-(
I agree that it could potentially return any error code, but according to the Windows documentation, the correct way of dealing with errors is to say: if( !SomeAPIThatMayFail( ... )) { DWORD error = GetLastError(); // Process error based on values from winerror.h } winerror.h defines: ERROR_FILE_NOT_FOUND // "The system cannot find the file specified." ERROR_PATH_NOT_FOUND // "The system cannot find the path specified." ERROR_FILE_EXISTS // "The file exists." ERROR_POTENTIAL_FILE_FOUND // "A file was found, but it may not be the correct file." I think these are the main ones relating to file/path existence. Note that ERROR_FILE_EXISTS will be returned by things like CopyFile when attemping to copy to a file that already exists and you haven't specified to overwrite that file. - Reece