This command writes the current buffer contents into the file @var{file}
in a format based on @var{format}, which is a list of format names. It
constructs the actual format starting from @var{format}, then appending
-any elements from the value of @code{buffer-file-format} with a non-nil
-@var{preserve} flag (see above), if they are not already present in
-@var{format}. It then updates @code{buffer-file-format} with this
-format, making it the default for future saves. Except for the
+any elements from the value of @code{buffer-file-format} with a
+non-@code{nil} @var{preserve} flag (see above), if they are not already
+present in @var{format}. It then updates @code{buffer-file-format} with
+this format, making it the default for future saves. Except for the
@var{format} argument, this command is similar to @code{write-file}. In
particular, @var{confirm} has the same meaning and interactive treatment
as the corresponding argument to @code{write-file}. @xref{Definition of