function test($arr) {
return $arr;
}
$arr = [1111];
test($arr);
debug_zval_dump($arr);c implementation code of test:
PHP_FUNCTION(test)
{
zval *arr;
ZEND_PARSE_PARAMETERS_START(1, 1)
Z_PARAM_ARRAY(arr)
ZEND_PARSE_PARAMETERS_END();
Z_TRY_ADDREF_P(arr);
RETURN_ARR(Z_ARR_P(arr));
}the final reference count of $arr in this code is 1 when test is defined. The kernel adds 1 through the macro Z _ TRY_ADDREF_P when the test method is called, and 1 when it is used as a parameter to debug_zval_dump. The question is why add 1 when calling the test method, rather than wait until the return value of test is needed?
$c = [33333];
$t = [
"a" => 111,
"c" => $c
];
$t["c"] = 222;
// test_set($t, "c", 2111); directly manipulate the array or call test_set to modify the value of the key "c". The reference count of the variable $c is subtracted by 1. The c implementation code of
test_set:
PHP_FUNCTION(test_set)
{
zval *arr, *val;
zend_string *key;
ZEND_PARSE_PARAMETERS_START(3, 3)
Z_PARAM_ARRAY_EX(arr, 0, 1)
Z_PARAM_STR(key)
Z_PARAM_ZVAL(val)
ZEND_PARSE_PARAMETERS_END();
Z_TRY_ADDREF_P(val);
zend_symtable_update(Z_ARRVAL_P(arr), key, val);
RETURN_TRUE;
}the reference is not subtracted by 1 in test_set. Where does the subtract 1 operation take place here?