符合中小企业对网站设计、功能常规化式的企业展示型网站建设
本套餐主要针对企业品牌型网站、中高端设计、前端互动体验...
商城网站建设因基本功能的需求不同费用上面也有很大的差别...
手机微信网站开发、微信官网、微信商城网站...
小编给大家分享一下C++如何使用资源句柄自动管理资源并RAII,相信大部分人都还不怎么了解,因此分享这篇文章给大家参考一下,希望大家阅读完这篇文章后大有收获,下面让我们一起去了解一下吧!
公司主营业务:成都网站设计、成都网站建设、移动网站开发等业务。帮助企业客户真正实现互联网宣传,提高企业的竞争能力。创新互联是一支青春激扬、勤奋敬业、活力青春激扬、勤奋敬业、活力澎湃、和谐高效的团队。公司秉承以“开放、自由、严谨、自律”为核心的企业文化,感谢他们对我们的高要求,感谢他们从不同领域给我们带来的挑战,让我们激情的团队有机会用头脑与智慧不断的给客户带来惊喜。创新互联推出个旧免费做网站回馈大家。
To avoid leaks and the complexity of manual resource management. C++'s language-enforced constructor/destructor symmetry mirrors the symmetry inherent in resource acquire/release function pairs such as fopen/fclose, lock/unlock, and new/delete. Whenever you deal with a resource that needs paired acquire/release function calls, encapsulate that resource in an object that enforces pairing for you -- acquire the resource in its constructor, and release it in its destructor.
避免手动管理资源时发生泄露和复杂性。C++语言鼓励构造函数/析构函数的对称性映射资源确保/释放函数对中包含的本质的对称性。这些函数对包括fopen/fclose,lock/unlock,new/deletre等。无论什么时候,你处理一个需要成对调用申请/释放函数时,用一个强制进行成对操作的对象封装资源--在它的构造函数中申请资源,在它的析构函数中释放资源。
Example, bad(反面示例)
Consider(考虑如下代码):
void send(X* x, cstring_span destination)
{
auto port = open_port(destination);
my_mutex.lock();
// ...
send(port, x);
// ...
my_mutex.unlock();
close_port(port);
delete x;
}
In this code, you have to remember to unlock, close_port, and delete on all paths, and do each exactly once. Further, if any of the code marked ... throws an exception, then x is leaked and my_mutex remains locked.
在这段代码中,你必须记得在所有路径上unlock,close_port和delete,而且确切地只做一次。另外,如果任何一处标有...的代码抛出了异常,那么x就会泄露,my_mutex会保持锁定。
Example(示例)
Consider(考虑):
void send(unique_ptr x, cstring_span destination) // x owns the X
{
Port port{destination}; // port owns the PortHandle
lock_guard guard{my_mutex}; // guard owns the lock
// ...
send(port, x);
// ...
} // automatically unlocks my_mutex and deletes the pointer in x
Now all resource cleanup is automatic, performed once on all paths whether or not there is an exception. As a bonus, the function now advertises that it takes over ownership of the pointer.
现在所有的资源清除都是自动的,在每条路径上执行一次。无论是否存在异常。作为额外的奖励,这个函数对外宣称它负责资源的所有权。
What is Port? A handy wrapper that encapsulates the resource:
什么是Port?一个封装资源的便利的容器。
class Port {
PortHandle port;
public:
Port(cstring_span destination) : port{open_port(destination)} { }
~Port() { close_port(port); }
operator PortHandle() { return port; }
// port handles can't usually be cloned, so disable copying and assignment if necessary
Port(const Port&) = delete;
Port& operator=(const Port&) = delete;
};
Where a resource is "ill-behaved" in that it isn't represented as a class with a destructor, wrap it in a class or use finally
当资源由于没有表现为一个带有虚构函数的类而存在"病态行为",用一个类封装它或者使用finally。
以上是“C++如何使用资源句柄自动管理资源并RAII”这篇文章的所有内容,感谢各位的阅读!相信大家都有了一定的了解,希望分享的内容对大家有所帮助,如果还想学习更多知识,欢迎关注创新互联行业资讯频道!