pmem2 API version 1.0



pmem2_map() - creates a mapping


#include <libpmem2.h>

struct pmem2_config;
struct pmem2_source;
struct pmem2_map;
int pmem2_map(const struct pmem2_config *config, const struct pmem2_source *source,
    struct pmem2_map **map_ptr);


The pmem2_map() function creates a new mapping in the virtual address space of the calling process. This function requires a configuration config of the mapping and the data source source.

For a mapping to succeed, the config structure must have the granularity parameter set to the appropriate level. See pmem2_config_set_required_store_granularity(3) and libpmem2(7) for more details.

If the pmem2_map() function succeeds in creating a new mapping it instantiates a new struct pmem2_map* object describing the mapping. The pointer to this newly created object is stored in the user-provided variable passed via the map_ptr pointer. If the mapping fails the variable pointed by map_ptr will contain a NULL value and appropriate error value will be returned. For a list of possible return values please see RETURN VALUE.

All struct pmem2_map objects created via the pmem2_map() function have to be destroyed using the pmem2_unmap() function. For details please see pmem2_unmap(3) manual page.


When pmem2_map() succeeds it returns 0. Otherwise, it returns one of the following error values:

  • PMEM2_E_GRANULARITY_NOT_SET - the store granularity for the mapping was not set in the provided config structure. Please seepmem2_config_set_required_store_granularity(3) and libpmem2(7).

  • PMEM2_E_MAP_RANGE - offset + length is too big to represent it using size_t data type

  • PMEM2_E_MAP_RANGE - end of the mapping (offset + length) is outside of the file. The file is too small.

  • PMEM2_E_SOURCE_EMPTY - mapped file has size equal to 0.

  • PMEM2_E_MAPPING_EXISTS - if the object exists before the function call. For details please see CreateFileMapping() manual pages. (Windows only)

  • PMEM2_E_OFFSET_UNALIGNED - argument unaligned, offset is not a multiple of the alignment required for specific *source. Please see pmem2_source_alignement(3).

  • PMEM2_E_LENGTH_UNALIGNED - argument unaligned, length is not a multiple of the alignment required for specific *source. Please see pmem2_source_alignement(3).

  • PMEM2_E_SRC_DEVDAX_PRIVATE - device DAX mapped with MAP_PRIVATE. (Linux only)

  • PMEM2_E_NOSUPP - when config-provided protection flags combination is not supported.

  • **PMEM2_E_NO_ACCESS - there is a conflict between mapping protection and file opening mode.

It can also return -EACCES, -EAGAIN, -EBADF, -ENFILE, -ENODEV, -ENOMEM, -EPERM, -ETXTBSY from the underlying mmap(2) function. It is used with and without MAP_ANONYMOUS.

-EACCES may be returned only if the file descriptor points to an append-only file.

It can also return all errors from the underlying pmem2_source_size() and pmem2_source_alignment() functions.


mmap(2), open(3), pmem2_config_set_required_store_granularity(3), pmem2_source_alignment(3), pmem2_source_from_fd(3), pmem2_source_size(3), pmem2_unmap(3), libpmem2(7) and

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