zero - source of zeroes
A zero special file is a source of zeroed unnamed memory.
Reads from a zero special file always return a buffer full
of zeroes. The file is of infinite length.
Writes to a zero special file are always successful, but the
data written is ignored.
Mapping a zero special file creates a zero-initialized
unnamed memory object of a length equal to the length of the
mapping and rounded up to the nearest page size as returned
by sysconf. Multiple processes can share such a zero special
file object provided a common ancestor mapped the object
fork(2), mmap(2), sysconf(3C)
Man(1) output converted with