.\"	$OpenBSD: SMR_PTR_GET.9,v 1.3 2019/07/05 04:46:26 dlg Exp $
.\"
.\" Copyright (c) 2019 Visa Hankala
.\"
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.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.Dd $Mdocdate: July 5 2019 $
.Dt SMR_PTR_GET 9
.Os
.Sh NAME
.Nm SMR_PTR_GET ,
.Nm SMR_PTR_GET_LOCKED ,
.Nm SMR_PTR_SET_LOCKED
.Nd safe memory reclamation pointer API
.Sh SYNOPSIS
.Ft TYPE
.Fn SMR_PTR_GET "TYPE *pptr"
.Ft TYPE
.Fn SMR_PTR_GET_LOCKED "TYPE *pptr"
.Ft void
.Fn SMR_PTR_SET_LOCKED "TYPE *pptr" "TYPE v"
.Sh DESCRIPTION
The SMR_PTR macros are used for accessing SMR-protected pointers.
.Pp
The macro
.Fn SMR_PTR_GET
reads the pointer referenced by
.Fa pptr
for dereferencing inside SMR read-side critical section.
.Pp
.Fn SMR_PTR_GET_LOCKED
reads the pointer referenced by
.Fa pptr
for dereferencing inside writer context.
.Pp
.Fn SMR_PTR_SET_LOCKED
writes value
.Fa v
to the pointer referenced by
.Fa pptr .
The operation issues a write-write memory barrier with
.Xr membar_producer 9
before the pointer write.
.Sh CONTEXT
.Fn SMR_PTR_GET ,
.Fn SMR_PTR_GET_LOCKED
and
.Fn SMR_PTR_SET_LOCKED
can be called during autoconf, from process context, or from interrupt context.
.Pp
.Fn SMR_PTR_GET
can be used from SMR read-side critical section.
.Fn SMR_PTR_GET_LOCKED
and
.Fn SMR_PTR_SET_LOCKED
can be used from writer context.
.Sh SEE ALSO
.Xr membar_producer 9 ,
.Xr SMR_LIST_INIT 9 ,
.Xr smr_read_enter 9
.Sh HISTORY
The SMR_PTR macros first appeared in
.Ox 6.5 .