Do we? In fact, I think the Fortran standard requires the default
REAL, INTEGER and LOGICAL to be of equal size (numeric storage unit).
So, only some combinations of these flags are conforming in general. I
do not think Octave needs to be bulletproof in this regard, at least
not until a real need arises from practice. When you're altering the
sizes of default types, you're often breaking standard-conformance,
and you're therefore supposed to know what you're doing. Anyway, a
common practical advice is to avoid LOGICALs in external interfaces at
all and just use INTEGERs.
cheers