Critical section

In concurrent programming a critical section is a piece of code that accesses a shared resource (data structure or device) that must not be concurrently accessed by more than one thread of execution.

參考 Log of /trunk/src/base/lock.h

lock (= critical section) 主要架構如下，注意 LockImpl 的技法 (opaque pointer)，很多 OS dependency 的 utility class 可以採用這樣的技法，事實上，Qt framework 狂用這招。

class Lock {
 public:
  Lock() : lock_() {}
  ~Lock() {}
  void Acquire() { lock_.Lock(); }
  void Release() { lock_.Unlock(); }

  bool Try() { return lock_.Try(); }
 private:
  LockImpl lock_;  // Platform specific underlying lock implementation.
};

在 Win 平台上，

::InitializeCriticalSectionAndSpinCount()

API 是最大的亮點，可以參考裡面寫的 comments. Standard posix 十分正常，看過就好。