'\"macro stdmacro
.if n .pH g7.zero @(#)zero	40.3 of 10/10/89
.\" Copyright 1989 AT&T
.nr X
.if \nX=0 .ds x} zero 7 "" "\&"
.if \nX=1 .ds x} zero 7 ""
.if \nX=2 .ds x} zero 7 "" "\&"
.if \nX=3 .ds x} zero "" "" "\&"
.TH \*(x}
.SH NAME
\f4zero\fP \- source of zeroes
.SH DESCRIPTION
A zero special file is a source of zeroed unnamed memory.
.P
Reads from a zero special file always return a buffer full of zeroes.
The file is of infinite length.
.P
Writes to a zero special file are always successful, but the data written is ignored.
.P
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
\f4sysconf\fP.
Multiple processes can share such a zero special file object provided a
common ancestor mapped the object
\f4MAP_SHARED\fP.
.SH FILES
\f4/dev/zero\fP
.SH "SEE ALSO"
\f4fork\fP(2),
\f4sysconf\fP(3C),
\f4mmap\fP(2)
