Some programmers might be tempted to "optimize" the code by putting std::move into the return statement like this:

T fn()
{

  T t;
  return std::move (t);
}
However, here the call to std::move precludes the NRVO, because it breaks the conditions specified in the C++ standard, namely [class.copy.elision]: the returned expression must be a name. The reason for this is that std::move returns a reference, and in general, the compiler can't know to what object the function returns a reference to. So GCC 9 will issue a warning (when -Wall is in effect):

t.C:8:20: warning: moving a local object in a return statement prevents copy elision [-Wpessimizing-move]
8 | return std::move (t);
  |        ~~~~~~~~~~^~~
t.C:8:20: note: remove ‘std::move’ call
--
FROM 221.219.211.*

string t;
return std::move(t);
标准move用法啊
要不然会调用拷贝构造函数，生成副本


【 在 pgw 的大作中提到: 】
: 这个return为什么要用move？
--
FROM 111.199.185.*

不需要吧
【 在 iwantfly 的大作中提到: 】
: string t;
: return std::move(t);
: 标准move用法啊
: ...................
--
FROM 167.220.233.*

这种影响编译器优化
【 在 iwantfly 的大作中提到: 】
: string t;
: return std::move(t);
: 标准move用法啊
: ...................
--
FROM 39.155.212.*

返回值优化
move只是转右值而已  
  
【 在 iwantfly (雷雷) 的大作中提到: 】
:  string t;
:  return std::move(t);
:  标准move用法啊
:  要不然会调用拷贝构造函数，生成副本
--
FROM 114.254.109.*