---
name: "pmem2_source_device_id"
section: "3"
platform: "linux"
package: "libpmem2-dev"
version: "1.13.1-1.1+b1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/pmem2_source_device_id"
---

# pmem2\_source\_device\_id(3)

returns the unique identifier of a device

## 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)](/libpmem2_unsafe_shutdown/7.md) 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)](/malloc/3.md), 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)](/fstat/2.md), 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)](/fstat/2.md), [**errno**(3)](/errno/3.md), [**malloc**(3)](/malloc/3.md), [**libpmem2\_unsafe\_shutdown**(7)](/libpmem2_unsafe_shutdown/7.md), and **\<https://pmem.io\>**