Std :: deque在程序退出之前不会释放内存 [英] Std::deque does not release memory until program exits

问题描述

在linux上，std :: deque在程序退出之前不会释放内存。完整的代码如下。

On linux, std::deque does not release memory until program exits. The complete code is below. Any help will be greatly appreciated!

#include <deque>
#include <vector>
#include <string>
#include <iostream>
#include <boost/shared_ptr.hpp>
#include <queue>
#include <list>
#include <cstdio>
#include <cstdlib>

typedef  boost::shared_ptr<std::vector<int> > VecPtr;
typedef  std::deque< VecPtr  > QueueType;

 char buf[1024];
 char line[1024];

 int main()
 {

  {

    int v=0;
    QueueType  deq;
    for(int i=0; i<30;++i)
    for(int j=0; j<1000;++j)
    for(int k=0;k<1000;++k)
    {
       VecPtr p( new std::vector<int>);
       deq.push_back(p);
    }

    std::cout<<"Done with increasing deq:deq size="<<deq.size()<<std::endl;
    sleep(20);

    std::cout<<"start decreasing deq size"<<std::endl;
    while(deq.size()>0)
    {
      deq.pop_front();
    }
    std::cout<<"done with decreasing deq size,deq size="<<deq.size()<<std::endl;
  }
  std::cin.getline(line,sizeof(line));
  return 0;
}

推荐答案

那是正确的， pop_front（）不会取消分配由 push_back（）
分配的存储空间。程序结束后，可以结束对象的生命周期。如果要在对象的生存期结束之前对其进行分配，请考虑使用 适用于C ++容器类的紧缩习惯。

That is correct, pop_front() does not deallocate storage that was allocated by push_back() If you want to deallocate it before the program ends, you can end the lifetime of the object. If you want to deallocate it before the lifetime of the object ends, consider using a "shrink-to-fit" idiom for C++ container classes.

QueueType().swap (deq); // C++98
deq.shrink_to_fit(); // C++11

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