常量字符串地址 [英] Constant strings address

问题描述

我的程序中有几个相同的字符串常量：

I have several identical string constants in my program:

const char* Ok()
{
  return "Ok";  
}

int main()
{
  const char* ok = "Ok";
}

是否保证它们具有相同的地址，即我可以写以下代码？我听说GNU C ++优化了字符串，因此它们具有相同的地址，我可以在程序中使用该功能吗？

Is there guarantee that they are have the same address, i.e. could I write the following code? I heard that GNU C++ optimize strings so they have the same address, could I use that feature in my programs?

int main()
{
  const char* ok = "Ok";
  if ( ok == Ok() ) // is it ok?
  ;
}

推荐答案

当然不能保证，但是

C ++标准说（2.13.4 / 2字符串文字）：

The C++ standard says (2.13.4/2 "String literals):

是否所有字符串文字都是唯一的（即存储在不重叠的对象中）是实现定义的。

Whether all string literals are distinct (that is, are stored in nonoverlapping objects) is implementation-defined.

要清楚，您不应该编写假定会进行此优化的代码-就像Chris Lutz所说的那样，依赖于此的C ++代码就是等待被破坏的代码。

To be clear, you shouldn't write code that assumes this optimization will take place - as Chris Lutz says, C++ code that relies on this is code that's waiting to be broken.

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