sunos man page for zero

zero(7D)							      Devices								  zero(7D)

NAME
       zero - source of zeroes

DESCRIPTION
       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.

FILES
       /dev/zero

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

SunOS 5.10							    3 Jul 1990								  zero(7D)