pmem2_source_device_usc3

Usage

Overview

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 information.

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:

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-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.