how to read a constant property in php extension?

Question

I use zend_declare_class_constant_stringl macro to declare a constant property,but i don't konw how to read the constant? the declare code :

zend_declare_class_constant_stringl(myclass_ce,ZEND_STRL("WEL"),ZEND_STRL("welcome\n") TSRMLS_CC);

I want use zend_read_property or zend_read_static_property to read the constant property but it doesn't work!

(1): I use zend_read_static_property:

ZEND_METHOD(myclass,getName){
zval *name;
char *str;
zend_class_entry *ce;
ce=Z_OBJCE_P(getThis());
name=zend_read_static_property(ce,ZEND_STRL("name"),0 TSRMLS_CC);
str=Z_STRVAL_P(name);
RETURN_STRINGL(str,Z_STRLEN_P(name),1);
}

[root@localhost myext]# php -f /var/www/html/myclass.php

Notice: Undefined property: myclass::$WEL in /var/www/html/myclass.php on line 3
(null)PHP Fatal error:  Access to undeclared static property: myclass::$name in      /var/www/html/myclass.php on line 5

(2) I use zend_read_property:

ZEND_METHOD(myclass,getName){
zval *name;
char *str;
zend_class_entry *ce;
ce=Z_OBJCE_P(getThis());
name=zend_read_property(ce,getThis(),ZEND_STRL("name"),0 TSRMLS_CC);
str=Z_STRVAL_P(name);
RETURN_STRINGL(str,Z_STRLEN_P(name),1);
}

[root@localhost myext]# php -f /var/www/html/myclass.php

Notice: Undefined property: myclass::$WEL in /var/www/html/myclass.php on line 3
(null)silenceperPHP Fatal error:  Access to undeclared static property: myclass::$BYE in Unknown on line 0

Answer 1

Use zend_get_constant_ex:

zval c;

if (zend_get_constant_ex(ZEND_STRL("ClassName::CONSTANT_NAME"), &c, NULL, 0 TSRMLS_CC) == SUCCESS) {
    // ...
}

The NULL is the class scope to perform the fetch from (if you want to use something like self). The 0 are flags, e.g. ZEND_FETCH_CLASS_SILENT.