本文介绍了c++11返回值优化还是搬家?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
I don't understand when I should use std::move and when I should let the compiler optimize... for example:
using SerialBuffer = vector< unsigned char >;
// let compiler optimize it
SerialBuffer read( size_t size ) const
{
SerialBuffer buffer( size );
read( begin( buffer ), end( buffer ) );
// Return Value Optimization
return buffer;
}
// explicit move
SerialBuffer read( size_t size ) const
{
SerialBuffer buffer( size );
read( begin( buffer ), end( buffer ) );
return move( buffer );
}
Which should I use?
解决方案
Use exclusively the first method:
Foo f()
{
Foo result;
mangle(result);
return result;
}
This will already allow the use of the move constructor, if one is available. In fact, a local variable can bind to an rvalue reference in a return statement precisely when copy elision is allowed.
Your second version actively prohibits copy elision. The first version is universally better.
这篇关于c++11返回值优化还是搬家?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！
本站部分内容来源互联网,如果有图片或者内容侵犯您的权益请联系我们删除！