boost compressedPair
作者:互联网
boost::compressed_pair behaves like std::pair. However, if one or both template parameters are empty classes, boost::compressed_pair consumes less memory. boost::compressed_pair uses a technique known as empty base class optimization.
#include <boost/compressed_pair.hpp> #include <utility> #include <iostream> struct empty [}; int main() { std::pair<int, empty> p; std::cout << sizeof(p) << std::endl; boost::compressed_pair<int, empty> cp; std::cout << sizeof(cp) << std::endl; return 0; }
输出为:
8
4
There is another difference between boost::compressed_pair and std::pair. the values stored in boost::compressed_pair are accessed through the member functions first() and second(), std::pair uses two indentically named member variables instead.
标签:std,compressedPair,compressed,pair,include,boost,empty 来源: https://www.cnblogs.com/sssblog/p/11122748.html