You've seen that your code is responsible for providing the main message receiving loop:
while (1) { // wait here for a message if ((ctp = dispatch_block (ctp)) == NULL) { perror ("Unable to dispatch_block"); exit (EXIT_FAILURE); } // handle the message dispatch_handler (ctp); }
This is very convenient, for it lets you place breakpoints on the receiving function and to intercept messages (perhaps with a debugger) during operation.
The library implements the magic inside of the dispatch_handler() function, because that's where the message is analyzed and disposed of through the connect and I/O functions tables we mentioned earlier.
In reality, the library consists of two cooperating layers: a base layer that provides raw resource manager functionality, and a POSIX layer that provides POSIX helper and default functions. We'll briefly define the two layers, and then in Resource manager structure, below, we'll pick up the details.