extern void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
extern mspace create_mspace_with_base(void* base, size_t capacity, int locked);
extern mspace create_mspace(size_t capacity, int locked);
extern void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
extern mspace create_mspace_with_base(void* base, size_t capacity, int locked);
extern mspace create_mspace(size_t capacity, int locked);