Creates or opens a named semaphore with the specified name.
The function has the following parameters:
- The name to be given the semaphore.
- How to create or open the semaphore.
- Unix style file mode to be used when creating the semaphore.
- The initial value assigned to the semaphore.
A pointer to a PRSem structure or
NULL/code> on error.
If the named semaphore doesn't exist and the
PR_SEM_CREATE flag is specified, the named semaphore is created. The created semaphore needs to be removed from the system with a
PR_SEM_CREATE is specified, the third argument is the access permission bits of the new semaphore (same interpretation as the mode argument to
PR_Open) and the fourth argument is the initial value of the new semaphore.
If PR_SEM_CREATE is not specified, the third and fourth arguments are ignored.