35 lines
935 B
Plaintext
35 lines
935 B
Plaintext
.\" @(#)zero.4s 1.1 94/10/31 SMI;
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.TH ZERO 4S "9 October 1987"
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.SH NAME
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zero \- source of zeroes
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.SH SYNOPSIS
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None; included with standard system.
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.IX "unnamed memory" "" "\fLzero\fP \(em source of zeroed unnamed memory"
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.SH DESCRIPTION
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.LP
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A zero special file is a source of zeroed unnamed memory.
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.LP
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Reads from a zero special file always return a buffer full of zeroes. The
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file is of infinite length.
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.LP
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Writes to a zero special file are always successful, but the data written is
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ignored.
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.LP
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Mapping a zero special file creates a zero-initialized unnamed memory
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object of a length equal to the length of the mapping and rounded up to the
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nearest page size as returned by
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.BR getpagesize (2).
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Multiple processes
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can share such a zero special file object provided a common ancestor mapped
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the object
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.BR \s-1MAP_SHARED\s0 .
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.SH FILES
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.PD 0
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.TP 20
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.B /dev/zero
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.PD
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.SH SEE ALSO
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.BR fork (2V),
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.BR getpagesize (2),
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.BR mmap (2)
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