NAME

       pmem2_map_from_existing() - creates a pmem2_map object from an existing mapping

SYNOPSIS

              #include <libpmem2.h>

              int pmem2_map_from_existing(struct pmem2_map **map, const struct pmem2_source *src,
                  void *addr, size_t len, enum pmem2_granularity gran);

DESCRIPTION

       The  pmem2_map_from_existing() returns a new *struct pmem2_map for mapping provided by the
       user. This function allows usage of libpmem2(7) API without pmem2_map_new(3)  for  mapping
       file.  Mapping  is defined by addr and len.  You have to specify underlying file as a src,
       and define granularity of this mapping. See pmem2_config_set_required_store_granularity(3)
       and libpmem2**(7) for more details.

       For   the  pmem2_map  object  created  by  the  pmem2_map_from_existing(3)  function,  the
       pmem2_map_delete(3) will only destroy the object, but it  won't  unmap  the  mapping  this
       object describes.

RETURN VALUE

       The pmem2_map_from_existing() function returns 0 when it succeeds or a negative error code
       on failure.

ERRORS

       The pmem2_map_from_existing() can fail with the following errors:

       PMEM2_E_MAPPING_EXISTS - when contiguous region (addr, addr + len) is  already  registered
       by libpmem2

       It can also return -ENOMEM from the underlying malloc(2) function.

SEE ALSO

       malloc(2), pmem2_map_delete(3), pmem2_map_new(3), pmem2_source_from_fd(3), libpmem2(7) and
       <https://pmem.io>