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>