NAME

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

SYNOPSIS

              #include <libpmem2.h>

              struct pmem2_source;
              int pmem2_source_device_usc(const struct pmem2_source *source, uint64_t *usc);

DESCRIPTION

       The  pmem2_source_device_usc() function retrieves the sum of the unsafe shutdown count(USC) values of all
       hardware devices backing the data source and stores it in *usc.

       Please refer to libpmem2_unsafe_shutdown(7) for detailed description on how to properly consume this  in‐
       formation.

RETURN VALUE

       The  pmem2_source_device_usc()  function  returns 0 on success.  If the function fails, the *usc variable
       content is left unmodified and a negative error code is returned.

ERRORS

       The pmem2_source_device_usc() can fail with the following errors:

       On all systems:

       • PMEM2_E_NOSUPP - the underlying platform does not expose unsafe shutdown count information.

       On Windows:

       • -errno equivalent of return code set by failing GetFinalPathNameByHandleW(), while  trying  to  resolve
         volume path from the file handle.

       • -errno set by failing malloc(3), while trying to allocate a buffer for storing volume path.

       • -errno  equivalent  of return code set by failing CreateFileW(), while trying to obtain a handle to the
         volume.

       • -errno equivalent of return code set by failing DeviceIoControl(), while trying to  obtain  volume  USC
         value.

       On Linux:

       • -errno set by failing fstat(2), while trying to validate the file descriptor.

       • -errno set by failing ndctl_new(), while trying to initiate a new NDCTL library context.

       • -errno set by failing ndctl_dimm_get_dirty_shutdown(), while trying to obtain DIMM USC value.

SEE ALSO

       fstat(2), errno(3), malloc(3), libpmem2_unsafe_shutdown(7), and <https://pmem.io>