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PMEM2_SOURCE_ALIGNMENT(3) PMDK Programmer's Manual PMEM2_SOURCE_ALIGNMENT(3)

NAME

pmem2_source_alignment() - returns data source alignment

SYNOPSIS


#include <libpmem2.h>
struct pmem2_source;
int pmem2_source_alignment(const struct pmem2_source *source, size_t *alignment);

    

DESCRIPTION

The pmem2_source_alignment() function retrieves the alignment of offset and length needed for pmem2_map_new(3) to succeed. The alignment is stored in *alignment.

RETURN VALUE

The pmem2_source_alignment() function returns 0 on success. If the function fails, the *alignment variable is left unmodified and a negative error code is returned.

ERRORS

The pmem2_source_alignment() can fail with the following errors:

On all systems:

PMEM2_E_INVALID_ALIGNMENT_VALUE - operating system returned unexpected alignment value (eg. it is not a power of two).

on Linux:

PMEM2_E_INVALID_FILE_TYPE - file descriptor points to a character device other than Device DAX.
PMEM2_E_INVALID_ALIGNMENT_FORMAT - kernel query for Device DAX alignment returned data in invalid format.
-errno set by failing fstat(2), while trying to validate the file descriptor.
-errno set by failing realpath(3), while trying to determine whether fd points to a Device DAX.
-errno set by failing read(2), while trying to determine Device DAX’s alignment.
-errno set by failing strtoull(3), while trying to determine Device DAX’s alignment.

On FreeBSD:

PMEM2_E_INVALID_FILE_TYPE - file descriptor points to a directory, block device, pipe, socket, or character device.
-errno set by failing fstat(2), while trying to validate the file descriptor.

SEE ALSO

errno(3), fstat(2), realpath(3), read(2), strtoull(3), pmem2_config_new(3), pmem2_source_from_handle(3), pmem2_source_from_fd(3), libpmem2(7) and <http://pmem.io>
2020-10-16 PMDK - pmem2 API version 1.0