view release on metacpan or  search on metacpan

shm_generic.h  view on Meta::CPAN

/*
 * shm_generic.h — Macro-template for shared-memory hash maps.
 *
 * Before including, define:
 *   SHM_PREFIX         — function prefix (e.g., shm_ii)
 *   SHM_NODE_TYPE      — node struct name
 *   SHM_VARIANT_ID     — unique integer for header validation
 *
 * Key type (choose one):
 *   SHM_KEY_IS_INT + SHM_KEY_INT_TYPE  — integer key
 *   (leave undefined for string keys via arena)
 *
 * Value type (choose one):
 *   SHM_VAL_IS_STR                      — string value via arena
 *   SHM_VAL_INT_TYPE                    — integer value
 *
 * Optional:
 *   SHM_HAS_COUNTERS  — generate incr/decr/incr_by and integer cas (integer values only)
 */

/* ================================================================
 * Part 1: Shared definitions (included once)
 * ================================================================ */

#ifndef SHM_DEFS_H
#define SHM_DEFS_H

#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <sys/mman.h>
#include <sys/stat.h>

#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#error "shm_generic.h: inline string packing requires little-endian architecture"
#endif
#include <sys/file.h>
#include <pthread.h>  /* pthread_atfork — available in libc on modern glibc; no -lpthread needed */
#include <sys/syscall.h>
#include <limits.h>
#include <signal.h>
#include <errno.h>
#include <linux/futex.h>

#ifdef __SSE2__
#include <emmintrin.h>
#endif

#define XXH_INLINE_ALL
#include "xxhash.h"

/* ---- Constants ---- */

#define SHM_MAGIC       0x53484D31U  /* "SHM1" */
#define SHM_VERSION     9
#define SHM_READER_SLOTS 1024  /* max concurrent reader processes for dead-process recovery */
#define SHM_INITIAL_CAP 16
#define SHM_MAX_STR_LEN 0x3FFFFFFFU  /* ~1GB, bit 30 reserved for inline flag */