NAME

       pmempool_feature_query(),  pmempool_feature_enable(),  pmempool_feature_disable()  - toggle or query pool
       set features

SYNOPSIS

              #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);

DESCRIPTION

       The feature argument accepts following values:

       • PMEMPOOL_FEAT_SINGLEHDR - only the first part in each replica contains the pool part internal metadata.
         This  value  can  be  used only with pmempool_feature_query().  It can not be enabled or disabled.  For
         details see poolset(5).

       • PMEMPOOL_FEAT_CKSUM_2K - 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 PMEMPOOL_FEAT_CKSUM_2K is disabled whole 4KiB is checksummed.

       • PMEMPOOL_FEAT_SHUTDOWN_STATE - enables additional check performed during pool open which verifies  pool
         consistency  in  the  presence  of  dirty  shutdown.  PMEMPOOL_FEAT_CKSUM_2K has to be enabled prior to
         PMEMPOOL_FEAT_SHUTDOWN_STATE otherwise enabling PMEMPOOL_FEAT_SHUTDOWN_STATE will fail.

       • PMEMPOOL_FEAT_CHECK_BAD_BLOCKS - enables checking bad blocks performed during opening a pool and fixing
         bad blocks performed by pmempool-sync during syncing a pool.  For details see pmempool-feature(1).

       The pmempool_feature_query() function checks state of feature in the pool set pointed by path.

       The pmempool_feature_enable() function enables feature in the pool set pointed by path.

       The pmempool_feature_disable() function disables feature in the pool set pointed by path.

COMPATIBILITY

       Poolsets  with features not defined in this document (e.g. enabled by the newer software version) are not
       supported.

DISCLAIMER

       pmempool_feature_query(), pmempool_feature_enable() and pmempool_feature_disable() are not fail safe.

RETURN VALUE

       On success, pmempool_feature_query() returns 0 if feature is disabled or 1 if it is enabled.   On  error,
       it returns -1 and sets errno accordingly.

       On success, pmempool_feature_enable() returns 0.  On error, it returns -1 and sets errno accordingly.

       On success, pmempool_feature_disable() returns 0.  On error, it returns -1 and sets errno accordingly.

       If non zero flags are provided errno is set to EINVAL and function returns -1.

SEE ALSO

       poolset(5) and <https://pmem.io>