6. Creating an Application with OpenAPI : Sample Code : How the Asynchronous Sample Code Works
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How the Asynchronous Sample Code Works
The asynchronous sample code consists of a number of sources files whose names begin with the prefix “apia”. The source files are compiled and linked to produce a single comprehensive demo program that provides a real-life example of using OpenAPI in a client/server environment. OpenAPI functions are called asynchronously: each OpenAPI function call is provided with a callback function, which notifies the demo program of the completion of the function call.
Though single-threaded, the demo program consists of two independent execution units: a server unit, which creates, registers, and waits for database events, and a client unit, which periodically raises database events. The main processing control in the demo program initializes one, the other, or both of the execution units, then loops calling IIapi_wait() until all asynchronous activity has ended. Each execution unit, when initialized, issues its first asynchronous request. The units regain execution control when their requests complete and continue issuing new requests until they reach their termination conditions.