ZERO(4D) Devices ZERO(4D)


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 MAP_SHARED.




fork(2), mmap(2), sysconf(3C)

illumos July 3, 1990 ZERO(4D)