Some file handlers may not support all combinations and forms of the
arguments @var{infile}, @var{buffer}, and @var{display}. For example,
-some file handlers might behave as if @var{display} was @code{nil},
+some file handlers might behave as if @var{display} were @code{nil},
regardless of the value actually passed. As another example, some
file handlers might not support separating standard output and error
output by way of the @var{buffer} argument.