Inter-Thread Communication and Resource Sharing

Functions for inter-thread communication. More...

Content
	Signal Events
	Synchronize threads using signals.
	Message Queue
	Exchange messages between threads in a FIFO-like operation.
	Memory Pool
	Manage thread-safe fixed-size blocks of dynamic memory.
	Mail Queue
	Exchange data between threads using a queue of memory blocks.
	Mutexes
	Synchronize resource access using Mutual Exclusion (Mutex).
	Semaphores
	Access shared resources simultaneously from different threads.

Description

In most applications, threads need to communicate with each other or access shared resources together. There are many ways to exchange data between threads, for example using shared data, polling loops and message passing.

Many resources in a microcontroller can be considered as serially-reusable. This means that they can be used repeatedly by different threads, but only by one thread at a time (for example communication peripherals such as UARTs, memory, and files that need to be modified).

The CMSIS-RTOS API provides different means to pass messages between threads to make inter-thread communication more efficient. Also, resource sharing is inherently supported. The following methods are available to the user:

Inter-Thread Communication

• Signal Events
• Message Queue
• Memory Pool
• Mail Queue

Resource Sharing

• Mutexes
• Semaphores