Be careful of using binary semaphores (via semBCreate) for mutual exclusion. There is a rather nasty problem known as priority inversion that can happen if you're not careful.
Binary semaphores are best used for synchronization like:
Forever() {
wait here until something happens;
do what must be done;
}
And in another piece of code:
signal that something must be done
That is, binary semaphores are usually found as a single instance (semTake in VxWorks or the synchronize method in the WPILib) and a semGive is located in another piece of code.
For mutual exclusion (i.e., to protect a piece of data from simultaneous access) the declaration would look more like:
m_mySemaphore = semMCreate(SEM_Q_PRIORITY | SEM_DELETE_SAFE | SEM_INVERSION_SAFE);
Then the use of the semaphore is more consistent with the WPILib
CRITICAL_REGION(m_mySemaphore);
...
END_REGION
construct.
Using a binary semaphore for mutual exclusion is what got NASA into trouble on Mars with the first rover (before Spirit, et al). They had to create a patch and use interpanetary FTP to upload it. Then they pressed the reset button from Earth and held their breath...
Fortunately, it worked.
HTH,
Mike