Roger, the page you've linked to describes an ODBC driver. Didn't you intend to refer to another page?
There is usually some configurable timeout, which specifies how long a
thread can wait for a connection. If the timeout expires before a connection becomes available for that thread, some kind of exception is thrown. Some connection pools even can have the timeout set to an infinite value, meaning the exception is never thrown and the thread(s) will wait for a connection indefinitely.
The best you can do, Ashish, is to have a look at the documentation of the connection pool implementation you're using.