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 <https://pmem.io>