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Persisting Data
The typical intent of using persistent memory is to save data persistently. For this, you
need to use one of three APIs that libpmemobj provides:
• Atomic operations
• Reserve/publish
• Transactional
Atomic Operations
The pmemobj_alloc() and its variants shown below are easy to use, but they are limited
in features, so additional coding is required by the developer:
int pmemobj_alloc(PMEMobjpool *pop, PMEMoid *oidp,
size_t size, uint64_t type_num, pmemobj_constr
constructor, void *arg);
int pmemobj_zalloc(PMEMobjpool *pop, PMEMoid *oidp,
size_t size, uint64_t type_num);
void pmemobj_free(PMEMoid *oidp);
int pmemobj_realloc(PMEMobjpool *pop, PMEMoid *oidp,
size_t size, uint64_t type_num);
int pmemobj_zrealloc(PMEMobjpool *pop, PMEMoid *oidp,
size_t size, uint64_t type_num);
int pmemobj_strdup(PMEMobjpool *pop, PMEMoid *oidp,
const char *s, uint64_t type_num);
int pmemobj_wcsdup(PMEMobjpool *pop, PMEMoid *oidp,
const wchar_t *s, uint64_t type_num);
The TOID-based wrappers for most of these functions include:
POBJ_NEW(PMEMobjpool *pop, TOID *oidp, TYPE,
pmemobj_constr constructor, void *arg)
POBJ_ALLOC(PMEMobjpool *pop, TOID *oidp, TYPE, size_t size,
pmemobj_constr constructor, void *arg)
POBJ_ZNEW(PMEMobjpool *pop, TOID *oidp, TYPE)
POBJ_ZALLOC(PMEMobjpool *pop, TOID *oidp, TYPE, size_t size)
Chapter 7 libpmemobj: a Native traNsaCtioNal objeCt store