Palm OS Network Programming

Connecting to the Network

Now that you have a reference to the Net Library, you can start calling Net Library functions. Generally your application will assume that any required configuration has already been done via the Network Panel of the Preferences application. But if you have to make any changes to the configuration, you must do them before connecting to the network.

Opening the Net Library

Before you can access the network, you must first open the Net Library. Call NetLibOpen to load and initialize the protocol stack:

Err NetLibOpen (UInt16 netLibRefNum, UInt16* ifErrsP);

The first parameter is, of course, the reference number. If any network interfaces fail to load, an error is stored in *ifErrsP.

NetLibOpen reads the network configuration information from the preferences database. It then loads and initializes the appropriate components of the network protocol stack. Any changes to the configuration made after NetLibOpen has been called have no effect until the protocol stack, or the specific interface to which the setting pertains, is shut down and loaded again.

NetLibOpen also creates a new task on the operating system for the protocol stack to run on, and initializes the mailbox queues that allow this task to communicate with the user interface task.

The protocol stack may include a network interface that uses a dial-up connection for network connectivity, such as the Point-to-Point Protocol (PPP) or the Serial Line Internet Protocol (SLIP). These drivers are ...