1()                         PMDK Programmer's Manual                         ()
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NAME

6       pmempool_feature_query(),    pmempool_feature_enable(),   pmempool_fea‐
7       ture_disable() - toggle or query pool set features
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SYNOPSIS

10              #include <libpmempool.h>
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12              int pmempool_feature_query(const char *path, enum pmempool_feature feature, unsigned flags);
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14              int pmempool_feature_enable(const char *path, enum pmempool_feature feature, unsigned flags);
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16              int pmempool_feature_disable(const char *path, enum pmempool_feature feature, unsigned flags);
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DESCRIPTION

19       The feature argument accepts following values:
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21       • PMEMPOOL_FEAT_SINGLEHDR - only the first part in  each  replica  con‐
22         tains  the  pool part internal metadata.  This value can be used only
23         with pmempool_feature_query().  It can not be  enabled  or  disabled.
24         For details see poolset(5).
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26       • PMEMPOOL_FEAT_CKSUM_2K  -  only  the first 2KiB of pool part internal
27         metadata is checksummed.  Other features may depend on  this  one  to
28         store  additional  metadata in otherwise unused second 2KiB part of a
29         header.  When PMEMPOOL_FEAT_CKSUM_2K is disabled whole 4KiB is check‐
30         summed.
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32       • PMEMPOOL_FEAT_SHUTDOWN_STATE  -  enables  additional  check performed
33         during pool open which verifies pool consistency in the  presence  of
34         dirty  shutdown.   PMEMPOOL_FEAT_CKSUM_2K  has to be enabled prior to
35         PMEMPOOL_FEAT_SHUTDOWN_STATE otherwise  enabling  PMEMPOOL_FEAT_SHUT‐
36         DOWN_STATE will fail.
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38       • PMEMPOOL_FEAT_CHECK_BAD_BLOCKS  -  enables  checking  bad blocks per‐
39         formed during opening a pool and fixing bad blocks performed by pmem‐
40         pool-sync  during  syncing  a  pool.   For  details see pmempool-fea‐
41         ture(1).
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43       The pmempool_feature_query() function checks state of  feature  in  the
44       pool set pointed by path.
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46       The  pmempool_feature_enable() function enables feature in the pool set
47       pointed by path.
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49       The pmempool_feature_disable() function disables feature  in  the  pool
50       set pointed by path.
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COMPATIBILITY

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

57       pmempool_feature_query(), pmempool_feature_enable()  and  pmempool_fea‐
58       ture_disable() are not fail safe.
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RETURN VALUE

61       On  success,  pmempool_feature_query() returns 0 if feature is disabled
62       or 1 if it is enabled.  On error, it returns -1 and sets errno  accord‐
63       ingly.
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65       On  success, pmempool_feature_enable() returns 0.  On error, it returns
66       -1 and sets errno accordingly.
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68       On success, pmempool_feature_disable() returns 0.  On error, it returns
69       -1 and sets errno accordingly.
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71       If  non zero flags are provided errno is set to EINVAL and function re‐
72       turns -1.
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SEE ALSO

75       poolset(5) and <https://pmem.io>
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79PMDK -                            2023-06-05                                ()
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