A Mutex (Mutual Exclusion) is a method used to gain exclusive rights to use a shared resource in programming. Often used when designing software in embedded systems using interrupts and/or RTOS.

Example

In a interrupt driven embedded system there are two devices connected to a CAN bus. Two independent software routines communicate independent of each other with Device A and Device B through a shared CAN bus. See drawing below.

Two software routines fighting for exclusive access to the shared CAN bus