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.\" Chris Torek.
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.\"	$OpenBSD: bzero.3,v 1.10 2014/01/22 21:06:45 tedu Exp $
.\"
.Dd $Mdocdate: January 22 2014 $
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.Dt EXPLICIT_BZERO 3bsd
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.Os
.Sh NAME
.Nm explicit_bzero
.Nd write zeroes to a byte string
.Sh LIBRARY
.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
.Lb libbsd
.Sh SYNOPSIS
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.In string.h
(See
.Xr libbsd 7
for include usage.)
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.Ft void
.Fn explicit_bzero "void *buf" "size_t len"
.Sh DESCRIPTION
The
.Fn explicit_bzero
function writes
.Fa len
zero bytes to the string
.Fa buf .
If
.Fa len
is zero,
.Fn explicit_bzero
does nothing.
.Pp
The
.Fn explicit_bzero
variant behaves the same as the
.Fn bzero
function, 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 bzero 3 ,
.Xr memset 3 ,
.Xr swab 3
.Sh HISTORY
The
.Fn explicit_bzero
function first appeared in
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.Ox 5.5 ,
glibc 2.25.