typedef struct shm_toc_entry
{
	uint64 key;	 /* Arbitrary identifier */
	Size offset; /* Offset, in bytes, from TOC start */
} shm_toc_entry;

struct shm_toc
{
	uint64 toc_magic;		  /* Magic number identifying this TOC */
	slock_t toc_mutex;		  /* Spinlock for mutual exclusion */
	Size toc_total_bytes;	  /* Bytes managed by this TOC */
	Size toc_allocated_bytes; /* Bytes allocated of those managed */
	uint32 toc_nentry;		  /* Number of entries in TOC */
	shm_toc_entry toc_entry[FLEXIBLE_ARRAY_MEMBER];
};