1	Synchronization
2	Sychronization Contents Mutexes Synchronized Interface Sequential Operations External Locking Auto Locking Sychronizing Smart Pointer Guarded Operations Internal Locking Execute Around Pattern
3	Mutex Common synchronization primitive intra-process, inter-process
4	Generalised Synchronization Synchronization primitives share intent
5	Terminology: Sequential Operation Concurrent callers synchronize operation access
6	Weak External Locking
7	Weak Solution Why try/catch/throw not in embedded C++ Bloat, more code than before Duplication, must be repeated every time Complexity, code is harder to follow Responsibility, is with callers Scalability, is poor Intrusive
8	Auto Lock “Resource Release in Finalisation” idiom
9	Stronger Solution Why? No try/catch/throw No bloat No duplication Not complex Non intrusive Scalable, easy to lock statement sequences But... Responsibility is still with callers User must perform two actions
10	Alternative Solution Synchronizing smart pointer
11	Synchronized Queue Pointer Can be refactored into template class
12	Synchronized Queue Pointer Implementation
13	Temporary Lock Can be nested inside synch_ptr class
14	Temporary Lock 'tors Copy c'tor?, copy assignment?
15	Temporary Lock Access Single statement granularity Don't use twice in same statement Non re-entrant lock will cause deadlock
16	Terminology: Guarded Operation Operation synchronizes access to itself
17	Weak Internal Locking
18	Stronger Internal Locking
19	Safe Solution Because... Encapsulated resource Simple model of use But... Locks at single operation level Sometimes need coarser granularity Eg, what you want to enqueue a sequence of tasks operations?
20	Flexible Solution Execute Around + Command pattern
21	Flexible Solution Execute Around + Query pattern
22	Concrete Command Class
23	Concrete Command Object