Zend API： zval_dtor, zval_ptr_dtor

 zval_dtor和zval_ptr_dtor是2个宏函数，定义在(zend_variables.h)：

#define zval_dtor(zvalue) _zval_dtor((zvalue) ZEND_FILE_LINE_CC)
#define zval_ptr_dtor(zval_ptr) _zval_ptr_dtor((zval_ptr) ZEND_FILE_LINE_CC)

_zval_dtor也是定义在( zend_variables.h ):

ZEND_API void _zval_dtor_func(zval *zvalue ZEND_FILE_LINE_DC);

static inline void _zval_dtor(zval *zvalue ZEND_FILE_LINE_DC)
{
	if (zvalue->type <= IS_BOOL) {
		return;
	}
	_zval_dtor_func(zvalue ZEND_FILE_LINE_RELAY_CC);
}

_zval_dtor_func定义在(zend_variables.c):

ZEND_API void _zval_dtor_func(zval *zvalue ZEND_FILE_LINE_DC)
{
	switch (Z_TYPE_P(zvalue) & IS_CONSTANT_TYPE_MASK) {
		case IS_STRING:
		case IS_CONSTANT:
			CHECK_ZVAL_STRING_REL(zvalue);
			STR_FREE_REL(zvalue->value.str.val);
			break;
		case IS_ARRAY:
		case IS_CONSTANT_ARRAY: {
				TSRMLS_FETCH();

				if (zvalue->value.ht && (zvalue->value.ht != &EG(symbol_table))) {
					zend_hash_destroy(zvalue->value.ht);
					FREE_HASHTABLE(zvalue->value.ht);
				}
			}
			break;
		case IS_OBJECT:
			{
				TSRMLS_FETCH();

				Z_OBJ_HT_P(zvalue)->del_ref(zvalue TSRMLS_CC);
			}
			break;
		case IS_RESOURCE:
			{
				TSRMLS_FETCH();

				/* destroy resource */
				zend_list_delete(zvalue->value.lval);
			}
			break;
		case IS_LONG:
		case IS_DOUBLE:
		case IS_BOOL:
		case IS_NULL:
		default:
			return;
			break;
	}
}

_zval_ptr_dtor定义在(zend_execute_API.c):

ZEND_API void _zval_ptr_dtor(zval **zval_ptr ZEND_FILE_LINE_DC) /* {{{ */
{
	zval *zv = *zval_ptr;

#if DEBUG_ZEND>=2
	printf("Reducing refcount for %x (%x): %d->%d\n", *zval_ptr, zval_ptr, Z_REFCOUNT_PP(zval_ptr), Z_REFCOUNT_PP(zval_ptr) - 1);
#endif
	Z_DELREF_P(zv);
	if (Z_REFCOUNT_P(zv) == 0) {
		TSRMLS_FETCH();

		if (zv != &EG(uninitialized_zval)) {
			GC_REMOVE_ZVAL_FROM_BUFFER(zv);
			zval_dtor(zv);
			efree_rel(zv);
		}
	} else {
		TSRMLS_FETCH();

		if (Z_REFCOUNT_P(zv) == 1) {
			Z_UNSET_ISREF_P(zv);
		}

		GC_ZVAL_CHECK_POSSIBLE_ROOT(zv);
	}
}

好了，结果就是一点 zval_ptr_dtor会调用zval_dtor来释放内容。所以不在使用某个zval变量的时候记得及时清除掉。