diff options
Diffstat (limited to 'doc/protocol')
| -rw-r--r-- | doc/protocol | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/doc/protocol b/doc/protocol index def8f6f..a846581 100644 --- a/doc/protocol +++ b/doc/protocol @@ -14,10 +14,14 @@ broadcast: with P(X): Z(W) Write NUL-terminate message to shared memory - with V(N): + with V(N): -- (1) Q := 0 Z(S) + -- (1) may be omitted if semaphores are known that + P(·), Z(·), V(·) cannot create a race condition + with a processes running Z(·). + listen: with V(S): @@ -29,6 +33,17 @@ listen: break with V(W): with P(S): - Z(S) - Z(N) + Z(S) + Z(N) + + +`V(a)` means that semaphore a is released. +`P(a)` means that semaphore a is acquired. +`Z(a)` means that the process waits for semaphore a to become 0. +`with P(a)` that `P(a)` is done before the entering the scope, +and `V(a)` is done when exiting the scope. It also means that +these actions [P(a) and V(a)] are undone when the process exits, +or if the call fails. +`with V(a)` that `V(a)` is like `with P(a)` that `P(a)` and +`V(a)` are exchanged. |