How can I print string url ?

I want to send data to url and read datas. I used sim808 gsm module. And I need to send gsm location .

 String url= "http://www.myhostname.tk/info.php?rep_id=123&rep_lat=" + (String)(latitude) + "&rep_long=" + (String)longitude;

Serial.println(url);

str_len = url.length() + 1;
Serial.println(str_len);

When I print the url, in serial monitor string length is equal to 1. Also url is not printed. What is the problem ?

Please post a complete program that illustrates the problem. It needs only to declare and initialise the variables used and illustrate that the concatenated String cannot be printed

In your original program do you have more than one variable named url each with its own scope (global and local, perhaps)