PHP7 zend 变数结构

typedef struct _zend_string     zend_string;
 
struct _zend_string {
struct _zend_string {
   zend_refcounted_h gc;
   zend_ulong        h;                /* hash value */
   size_t            len;
   char              val[1];
};

typedef struct _zend_array     zend_array;
struct _zend_array {
   zend_refcounted_h gc;
   union {
      struct {
         ZEND_ENDIAN_LOHI_4(
            zend_uchar    flags,
            zend_uchar    nApplyCount,
            zend_uchar    nIteratorsCount,
            zend_uchar    consistency)
      } v;
      uint32_t flags;
   } u;
   uint32_t          nTableMask;
   Bucket           *arData;
   uint32_t          nNumUsed;
   uint32_t          nNumOfElements;
   uint32_t          nTableSize;
   uint32_t          nInternalPointer;
   zend_long         nNextFreeElement;
   dtor_func_t       pDestructor;
};

typedef struct _zval_struct     zval;
 
struct _zval_struct {
    zend_value        value;            /* value */
    union {
        struct {
            ZEND_ENDIAN_LOHI_4(
                zend_uchar    type,         /* active type */
                zend_uchar    type_flags,
                zend_uchar    const_flags,
                zend_uchar    reserved)     /* call info for EX(This) */
        } v;
        uint32_t type_info;
    } u1;
    union {
        uint32_t     next;                 /* hash collision chain */
        uint32_t     cache_slot;           /* literal cache slot */
        uint32_t     lineno;               /* line number (for ast nodes) */
        uint32_t     num_args;             /* arguments number for EX(This) */
        uint32_t     fe_pos;               /* foreach position */
        uint32_t     fe_iter_idx;          /* foreach iterator index */
        uint32_t     access_flags;         /* class constant access flags */
        uint32_t     property_guard;       /* single property guard */
        uint32_t     extra;                /* not further specified */
    } u2;
};

typedef union _zend_value {
   zend_long         lval;            /* long value */
   double            dval;            /* double value */
   zend_refcounted  *counted;
   zend_string      *str;
   zend_array       *arr;
   zend_object      *obj;
   zend_resource    *res;
   zend_reference   *ref;
   zend_ast_ref     *ast;
   zval             *zv;
   void             *ptr;
   zend_class_entry *ce;
   zend_function    *func;
   struct {
      uint32_t w1;
      uint32_t w2;
   } ww;
} zend_value;

typedef struct _zend_refcounted_h {
   uint32_t         refcount;         /* reference counter 32-bit */
   union {
      struct {
         ZEND_ENDIAN_LOHI_3(
            zend_uchar    type,
            zend_uchar    flags,    /* used for strings & objects */
            uint16_t      gc_info)  /* keeps GC root number (or 0) and color */
      } v;
      uint32_t type_info;
   } u;
} zend_refcounted_h;

// static zend_always_inline zend_string *zend_string_init(const char *str, size_t len, int persistent)
// #define pemalloc(size, persistent) ((persistent)?__zend_malloc(size):emalloc(size))
 
std::string str = "abc";
zend_string *zstr = zend_string_init((char*) str.c_str(), str.size(), 0);