.\" Automatically generated by Pandoc 2.9.2.1
.\"
.TH "" "" "2023-05-31" "PMDK - " "PMDK Programmer's Manual"
.hy
.\" SPDX-License-Identifier: BSD-3-Clause
.\" Copyright 2018-2022, Intel Corporation
.SH NAME
.PP
\f[B]pmempool_feature_query\f[R](), \f[B]pmempool_feature_enable\f[R](),
\f[B]pmempool_feature_disable\f[R]() - 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[R]
.fi
.SH DESCRIPTION
.PP
The \f[I]feature\f[R] argument accepts following values:
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_SINGLEHDR\f[R] - 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[R]().
It can not be enabled or disabled.
For details see \f[B]poolset\f[R](5).
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_CKSUM_2K\f[R] - 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[R] is disabled whole 4KiB is
checksummed.
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_SHUTDOWN_STATE\f[R] - enables additional check
performed during pool open which verifies pool consistency in the
presence of dirty shutdown.
\f[B]PMEMPOOL_FEAT_CKSUM_2K\f[R] has to be enabled prior to
\f[B]PMEMPOOL_FEAT_SHUTDOWN_STATE\f[R] otherwise enabling
\f[B]PMEMPOOL_FEAT_SHUTDOWN_STATE\f[R] will fail.
.IP \[bu] 2
\f[B]PMEMPOOL_FEAT_CHECK_BAD_BLOCKS\f[R] - 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[R](1).
.PP
The \f[B]pmempool_feature_query\f[R]() function checks state of
\f[I]feature\f[R] in the pool set pointed by \f[I]path\f[R].
.PP
The \f[B]pmempool_feature_enable\f[R]() function enables
\f[I]feature\f[R] in the pool set pointed by \f[I]path\f[R].
.PP
The \f[B]pmempool_feature_disable\f[R]() function disables
\f[I]feature\f[R] in the pool set pointed by \f[I]path\f[R].
.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[R](), \f[B]pmempool_feature_enable\f[R]()
and \f[B]pmempool_feature_disable\f[R]() are not fail safe.
.SH RETURN VALUE
.PP
On success, \f[B]pmempool_feature_query\f[R]() returns 0 if
\f[I]feature\f[R] is disabled or 1 if it is enabled.
On error, it returns -1 and sets \f[I]errno\f[R] accordingly.
.PP
On success, \f[B]pmempool_feature_enable\f[R]() returns 0.
On error, it returns -1 and sets \f[I]errno\f[R] accordingly.
.PP
On success, \f[B]pmempool_feature_disable\f[R]() returns 0.
On error, it returns -1 and sets \f[I]errno\f[R] accordingly.
.PP
If non zero \f[I]flags\f[R] are provided \f[B]errno\f[R] is set to
EINVAL and function returns -1.
.SH SEE ALSO
.PP
\f[B]poolset\f[R](5) and \f[B]<https://pmem.io>\f[R]