About

seekhole?

SEEK_HOLE
Adjust the file offset to the next hole in the file greater
than or equal to offset.  If offset points into the middle of
a hole, then the file offset is set to offset.  If there is no
hole past offset, then the file offset is adjusted to the end
of the file (i.e., there is an implicit hole at the end of any
file).
                                  - lseek(2) man page

Yes, all the better IO related names were taken.