func (e *errorString) Error() string {
return e.s
}
+
+// ErrUnsupported indicates that a requested operation cannot be performed,
+// because it is unsupported. For example, a call to os.Link when using a
+// file system that does not support hard links.
+//
+// Functions and methods should not return this error but should instead
+// return an error including appropriate context that satisfies
+//
+// errors.Is(err, errors.ErrUnsupported)
+//
+// either by directly wrapping ErrUnsupported or by implementing an Is method.
+//
+// Functions and methods should document the cases in which an error
+// wrapping this will be returned.
+var ErrUnsupported = New("unsupported operation")