fstream - How to increase the buffer size used by rdbuf in c++

Question

I am using below c++ code to copy a file (size is around 1.5-2 gb) from one location to another.

#include <fstream>

int main()
{
    std::ifstream  src("source_path/file.mp4", std::ios::binary);
    std::ofstream  dst("destination_path/fileCopy.mp4",   std::ios::binary);

    dst << src.rdbuf();
}

I have taken this code from here Copy a file in a sane, safe and efficient way

This code is taking around 45 seconds to copy the file from source to destination. I know here the rdbuf must have some buffer size associated with it, Actually I want to increase the buffer size for more better performance, How can I increase the buffer ?

Answer 1

等待大神答复