锁的选项有3个结构类型以及3个它们的常量
struct defer_lock_t {}; struct try_to_lock_t {}; struct adopt_lock_t {}; const defer_lock_t defer_lock; const try_to_lock_t try_to_lock; const adopt_lock_t adopt_lock;
锁的选项用于范围锁的构造函数，它们有下面的含义：
原文：http://www.cnblogs.com/sqxy110/p/5249710.html