.\" Automatically generated by Pandoc 2.0.6
.\"
.TH "PMEMPOOL_FEATURE_QUERY" "3" "2022-08-25" "PMDK - pmempool API version 1.3" "PMDK Programmer's Manual"
.hy
.\" SPDX-License-Identifier: BSD-3-Clause
.\" Copyright 2018, Intel Corporation
.SH NAME
.PP
\f[B]pmempool_feature_query\f[](), \f[B]pmempool_feature_enable\f[](),
\f[B]pmempool_feature_disable\f[]() \- toggle or query pool set features
.SH SYNOPSIS
.IP
.nf
\f[C]
#include\ <libpmempool.h>

int\ pmempool_feature_query(const\ char\ *path,\ enum\ pmempool_feature\ feature,\ unsigned\ flags);

int\ pmempool_feature_enable(const\ char\ *path,\ enum\ pmempool_feature\ feature,\ unsigned\ flags);

int\ pmempool_feature_disable(const\ char\ *path,\ enum\ pmempool_feature\ feature,\ unsigned\ flags);
\f[]
.fi
.SH DESCRIPTION
.PP
The \f[I]feature\f[] argument accepts following values:
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_SINGLEHDR\f[] \- only the first part in each replica
contains the pool part internal metadata.
This value can be used only with \f[B]pmempool_feature_query\f[]().
It can not be enabled or disabled.
For details see \f[B]poolset\f[](5).
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_CKSUM_2K\f[] \- only the first 2KiB of pool part
internal metadata is checksummed.
Other features may depend on this one to store additional metadata in
otherwise unused second 2KiB part of a header.
When \f[B]PMEMPOOL_FEAT_CKSUM_2K\f[] is disabled whole 4KiB is
checksummed.
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_SHUTDOWN_STATE\f[] \- enables additional check
performed during pool open which verifies pool consistency in the
presence of dirty shutdown.
\f[B]PMEMPOOL_FEAT_CKSUM_2K\f[] has to be enabled prior to
\f[B]PMEMPOOL_FEAT_SHUTDOWN_STATE\f[] otherwise enabling
\f[B]PMEMPOOL_FEAT_SHUTDOWN_STATE\f[] will fail.
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_CHECK_BAD_BLOCKS\f[] \- enables checking bad blocks
performed during opening a pool and fixing bad blocks performed by
pmempool\-sync during syncing a pool.
For details see \f[B]pmempool\-feature\f[](1).
.PP
The \f[B]pmempool_feature_query\f[]() function checks state of
\f[I]feature\f[] in the pool set pointed by \f[I]path\f[].
.PP
The \f[B]pmempool_feature_enable\f[]() function enables \f[I]feature\f[]
in the pool set pointed by \f[I]path\f[].
.PP
The \f[B]pmempool_feature_disable\f[]() function disables
\f[I]feature\f[] in the pool set pointed by \f[I]path\f[].
.SH COMPATIBILITY
.PP
Poolsets with features not defined in this document (e.g.\ enabled by
the newer software version) are not supported.
.SH DISCLAIMER
.PP
\f[B]pmempool_feature_query\f[](), \f[B]pmempool_feature_enable\f[]()
and \f[B]pmempool_feature_disable\f[]() are not fail safe.
.SH RETURN VALUE
.PP
On success, \f[B]pmempool_feature_query\f[]() returns 0 if
\f[I]feature\f[] is disabled or 1 if it is enabled.
On error, it returns \-1 and sets \f[I]errno\f[] accordingly.
.PP
On success, \f[B]pmempool_feature_enable\f[]() returns 0.
On error, it returns \-1 and sets \f[I]errno\f[] accordingly.
.PP
On success, \f[B]pmempool_feature_disable\f[]() returns 0.
On error, it returns \-1 and sets \f[I]errno\f[] accordingly.
.PP
If \f[I]path\f[] points poolset with remote replica \f[B]errno\f[] is
set to EINVAL and function returns \-1.
.PP
If non zero \f[I]flags\f[] are provided \f[B]errno\f[] is set to EINVAL
and function returns \-1.
.SH SEE ALSO
.PP
\f[B]poolset\f[](5) and \f[B]<https://pmem.io>\f[]