Asynchronous applications are designed to make constructive use of time that would otherwise be spent waiting for certain operations to complete. Typically, reading from and writing to a network or external device is much slower than straightforward program execution. Also, it takes time for a server to process commands and send results back to the client application.
Some applications execute several tasks that involve idle time. For example, an interactive application might:
Wait for user input
Execute commands on a connection to Server X
Execute commands on a connection to Server Y
Client-Library’s asynchronous modes help such an application to execute these tasks concurrently. When executing server commands, routines that send commands or read results return immediately. This means the application calls another routine to start command operations on another connection, and the application responds more quickly to user input.
Client-Library’s asynchronous mode is one method for achieving concurrent task execution. The other is to use multiple threads. For information on using Client-Library in a multithreaded environment, see “Multithreaded programming”.
