const char* helloWorld() {
    return "Hello World";
}

I have above function c returing const char*, how can I convert char to zval as use in below php method

PHP_METHOD(Hoom_Loader, say) {
    zval ok;
    zval *this_ptr = getThis();

    ZVAL_UNDEF(&ok);

    ok=helloWorld();
    zend_print_zval(&ok, 0);
}

I'm getting this error

error: incompatible types when assigning to type ‘zval {aka struct _zval_struct}’ from type ‘const char *’
 ok=helloWorld();
       ^