Why is FileInfo.Length of type "long"?

I was just wondering whether anyone knows why the property FileInfo.Length is of type long instead of ulong? I don't think the size o开发者_如何学运维f a file can ever be negative.

Was this a general design decision for the .NET framework, since other length properties (e.g. string.Length) are also of type long?

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ulong isn't a CLS-compliant type. The framework tends to use CLS-compliant types where possible.