PMEM2_MAP_FROM_EXISTING(3)

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>