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The BSD socket API interfaces to internal structures and variables (i.e., data) that are maintained by µC/TCP-IP. A binary semaphore (the global lock in the figure µC/TCP-IP Task model) is used to guard access to this data to ensure exclusive access. In order to read or write to this data, a task needs to acquire the binary semaphore before it can access the data and release it when finished. Of course, the application tasks do not have to know anything about this semaphore nor the data since its use is encapsulated by functions within µC/TCP-IP.
The figure µC/TCP-IP Task model shows a simplified task model of µC/TCP-IP along with application tasks.
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