T*
or owner<T*>
to designate a single object(使用T*或owner<T*>指明唯一对象)
Readability: it makes the meaning of a plain pointer clear. Enables significant tool support.
可读性:这可以让裸指针的含义更明确。使重要的工具支持有效。
译者注
译者注:owner<T*>是gsl(准则支持库)提供的一个功能,从编译的角度来看和T*的含义一致,但是附加了所有权语义,可以帮助程序员理解代码和工具检查。
In traditional C and C++ code, plain T*
is used for many weakly-related purposes, such as:
在传统的C和C++代码中,裸指针用于很多没有什么关系的目的,例如:
nullptr
持有nullptr
This makes it hard to understand what the code does and is supposed to do. It complicates checking and tool support.
这样做的结果是很难理解代码在做什么和被预期做什么。无论是检查还是工具支持都会复杂。
void use(int* p, int n, char* s, int* q)
{
p[n - 1] = 666; // Bad: we don't know if p points to n elements;
// assume it does not or use span<int>
cout << s; // Bad: we don't know if that s points to a zero-terminated array of char;
// assume it does not or use zstring
delete q; // Bad: we don't know if *q is allocated on the free store;
// assume it does not or use owner
}
译者注:这可能是我们每天都能见到的指针用法,很难看出它们到底是前面提供的那种用法。
better(稍好)
void use2(span<int> p, zstring s, owner<int*> q)
{
p[p.size() - 1] = 666; // OK, a range error can be caught
cout << s; // OK
delete q; // OK
}
Note(注意)
owner<T*>
represents ownership, zstring
represents a C-style string.
owner<T*>表现所有权,zstring表达C风格的字符串
Also: Assume that a T*
obtained from a smart pointer to T
(e.g., unique_ptr<T>
) points to a single element.
参考:假定T*是从指向T的智能指针(例如unique_prt<T>)获取,指向单一对象的指针。
See also: Support library
参考:支持库。
See also: Do not pass an array as a single pointer
参考:不要使用单一指针传递数组