彻底搞懂PHP 变量结构体

// 1. zval
typedef struct _zval_struct {
 zvalue_value value;
 zend_uint refcount__gc;
 zend_uchar type;
 zend_uchar is_ref__gc;
} zval;
// 2. zvalue_value
typedef union _zvalue_value {
 long lval;  // 用于 bool 类型、整型和资源类型
 double dval; // 用于浮点类型
 struct {  // 用于字符串
  char val;
  int len;
 } str;
 HashTable ht; // 用于数组
 zend_object_value obj; // 用于对象
 zend_ast ast; // 用于常量表达式(PHP5.6 才有)
} zvalue_value;
// 3. zend_object_value
typedef struct _zend_object_value {
 zend_object_handle handle;
 const zend_object_handlers handlers;
} zend_object_value;
// 4. zend_object_handle
typedef unsigned int zend_object_handle;

// 1. 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  aess_flags;   / class constant aess flags /
  uint32_t  property_guard;  / single property guard /
 } u2;
};
// 2. zend_value
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;