mutex

In NXC the mutex type is a 32-bit value that is used to synchronize access to resources shared across multiple threads.

For this reason there is never a reason to declare a mutex variable inside a task or a function. It is designed for global variables that all tasks or functions can Acquire or Release in order to obtain exclusive access to a resource that other tasks or functions are also trying to use.

mutex motorMutex;
task t1()
{
   while (true) {
     Acquire(motorMutex);
     // use the motor(s) protected by this mutex.
     Release(motorMutex);
     Wait(MS_500);
   }
}
task t2()
{
   while (true) {
     Acquire(motorMutex);
     // use the motor(s) protected by this mutex.
     Release(motorMutex);
     Wait(MS_200);
   }
}
task main()
{
  Precedes(t1, t2);
}