plucky (3) pmem2_source_alignment.3.gz

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>