Am 23.04.2017 um 08:42 schrieb Peter Krefting:

René Scharfe:

quoted

The offset is only needed in the ZIP64 extra record for the central
header (in zip_dir) -- the local header has no offset field.

Good point.

The zip64 local header does have an offset field, though. I thought that
was the zip_offset value, but that doesn't make sense, I'm not quite
sure what it is supposed to store. I need to investigate that further, I
assume.

Let's get the naming straight: There is no "zip64 local header". There 
is a "zip64 extra record" for the "zip local header". The zip64 extra 
data record has an offset field, but since the local header does not 
have an offset field, the offset field in the corresponding zip64 extra 
data record is always omitted.

-- Hannes