未命名命名空间优于静态命名空间?
未命名命名空间如何优于 static 关键字?
How are unnamed namespaces superior to the static keyword?
推荐答案
您基本上是指 C++03 标准中的 §7.3.1.1/2 部分，
You're basically referring to the section §7.3.1.1/2 from the C++03 Standard,
static 关键字的使用是在声明对象时不推荐使用命名空间范围；这未命名命名空间提供了一个优越的替代.
The use of the static keyword is deprecated when declaring objects in a namespace scope; the unnamed-namespace provides a superior alternative.
请注意，此段落已在 C++11 中删除.static 函数已按照标准 不再被弃用！
Note that this paragraph was already removed in C++11. static functions are per standard no longer deprecated!
尽管如此，未命名的 namespace 优于 static 关键字，主要是因为关键字 static 仅适用于 变量 声明和函数，而不是用户定义的类型.
Nonetheless, unnamed namespace's are superior to the static keyword, primarily because the keyword static applies only to the variables declarations and functions, not to the user-defined types.
以下代码在 C++ 中有效:
The following code is valid in C++:
//legal code
static int sample_function() { /* function body */ }
static int sample_variable;
但此代码无效:
//illegal code
static class sample_class { /* class body */ };
static struct sample_struct { /* struct body */ };
所以解决方案是，未命名(又名匿名)namespace，就是这样:
So the solution is, unnamed (aka anonymous) namespace, which is this:
//legal code
namespace
{
class sample_class { /* class body */ };
struct sample_struct { /* struct body */ };
}
希望它能解释为什么未命名的namespace优于static.
Hope it explains that why unnamed namespace is superior to static.
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