NAME

       pmem2_source_device_id() - returns the unique identifier of a device

SYNOPSIS

              #include <libpmem2.h>

              struct pmem2_source;
              int pmem2_source_device_id(const struct pmem2_source *source, char *id, size_t *len);

DESCRIPTION

       The pmem2_source_device_id() function retrieves a unique identifier of all NVDIMMs backing
       the data source.  This function has two operating modes:

       • if *id is NULL the  function  calculates  a  buffer  length  required  for  storing  the
         identifier  of the *source device and puts this length in *len The more hardware devices
         back the data source, the longer the length is.

       • if *id is not NULL it must point to a buffer of length *len  provided  by  the  previous
         call  to  this  function.   On  success,  pmem2_source_device_id()  will  store a unique
         identifier of all hardware devices backing the data source.

       For details on how to use the unique identifier for detecting the unsafe  shutdown  please
       refer to libpmem2_unsafe_shutdown(7) manual page.

RETURN VALUE

       The  pmem2_source_device_id()  function  returns 0 on success.  If the function fails, the
       *id and *len variables contents are left unmodified and a negative error code is returned.

ERRORS

       The pmem2_source_device_id() can fail with the following errors:

       On all systems:

       • PMEM2_E_BUFFER_TOO_SMALL - the provided buffer of length *len is too small to store  the
         full identifier of the backing devices.

       • PMEM2_E_NOSUPP - the underlying platform does not expose hardware identification.

       On Windows:

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

SEE ALSO

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