1()                         PMDK Programmer's Manual                         ()
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NAME

6       pmem2_source_device_usc()  -  returns the unsafe shutdown counter value
7       of a device
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SYNOPSIS

10              #include <libpmem2.h>
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12              struct pmem2_source;
13              int pmem2_source_device_usc(const struct pmem2_source *source, uint64_t *usc);
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DESCRIPTION

16       The pmem2_source_device_usc() function retrieves the sum of the  unsafe
17       shutdown  count(USC)  values  of  all hardware devices backing the data
18       source and stores it in *usc.
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20       Please refer to libpmem2_unsafe_shutdown(7) for detailed description on
21       how to properly consume this information.
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RETURN VALUE

24       The  pmem2_source_device_usc()  function  returns 0 on success.  If the
25       function fails, the *usc variable content is left unmodified and a neg‐
26       ative error code is returned.
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ERRORS

29       The pmem2_source_device_usc() can fail with the following errors:
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31       On all systems:
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33       • PMEM2_E_NOSUPP - the underlying platform does not expose unsafe shut‐
34         down count information.
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36       On Windows:
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38       • -errno equivalent of return code set by  failing  GetFinalPathNameBy‐
39         HandleW(), while trying to resolve volume path from the file handle.
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41       • -errno  set  by  failing malloc(3), while trying to allocate a buffer
42         for storing volume path.
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44       • -errno equivalent of return code set by failing CreateFileW(),  while
45         trying to obtain a handle to the volume.
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47       • -errno  equivalent  of  return code set by failing DeviceIoControl(),
48         while trying to obtain volume USC value.
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50       On Linux:
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52       • -errno set by failing fstat(2), while trying to validate the file de‐
53         scriptor.
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55       • -errno set by failing ndctl_new(), while trying to initiate a new ND‐
56         CTL library context.
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58       • -errno set by failing ndctl_dimm_get_dirty_shutdown(),  while  trying
59         to obtain DIMM USC value.
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SEE ALSO

62       fstat(2),   errno(3),   malloc(3),   libpmem2_unsafe_shutdown(7),   and
63       <https://pmem.io>
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67PMDK -                            2023-06-05                                ()
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