Pathname identifying location of buffer .
An external format spec.
A buffer whose contents are examined.
Length (an integer) up to which buffer should be examined.
Compares
pathname
(using
pathname-match-p
) with elements of *filename-pattern-encoding-matches*.
If a match is found, merges ef-spec with the corresponding external format spec and returns the result as new-ef-spec . Thus it does not override a supplied ef-spec .