lib/libc/string/bzero.3 - master - nerfur/openbsd-src

lib/libc/string/bzero.3
92 строки3 KB
schwarze
Add STANDARDS: denis@ spotted that it was missing.
12 окт 2017, 18:22
12 окт 2017, 18:220f27326
.\" Copyright (c) 1990, 1991 The Regents of the University of California.
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.\" Chris Torek.
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.\"	$OpenBSD: bzero.3,v 1.13 2017/10/12 15:22:32 schwarze Exp $
.\"
.Dd $Mdocdate: October 12 2017 $
.Dt BZERO 3
.Os
.Sh NAME
.Nm bzero ,
.Nm explicit_bzero
.Nd write zeroes to a byte string
.Sh SYNOPSIS
.In strings.h
.Ft void
.Fn bzero "void *b" "size_t len"
.In string.h
.Ft void
.Fn explicit_bzero "void *b" "size_t len"
.Sh DESCRIPTION
The
.Fn bzero
function writes
.Fa len
zero bytes to the string
.Fa b .
If
.Fa len
is zero,
.Fn bzero
does nothing.
.Pp
The
.Fn explicit_bzero
variant behaves the same, but will not be removed by a compiler's dead store
optimization pass, making it useful for clearing sensitive memory such as a
password.
.Sh SEE ALSO
.Xr memset 3 ,
.Xr swab 3
.Sh STANDARDS
The
.Fn bzero
function conforms to the X/Open System Interfaces option of the
.St -p1003.1-2004
specification.
It was removed from the standard in
.St -p1003.1-2008 ,
which recommends using
.Xr memset 3
instead.
.Pp
The
.Fn explicit_bzero
function is an
.Ox
extension.
.Sh HISTORY
The
.Fn bzero
function first appeared in
.Bx 4.2 .
The
.Fn explicit_bzero
function first appeared in
.Ox 5.5 .