执行以下代码#include ＃包括int main() { std::fstream fs{\'/dev/shm/test.bin\', std::ios::in | std::ios::out | std::ios::binary | st...

执行以下代码

#include <iostream>
#include <fstream>

int main() {
    std::fstream fs{"/dev/shm/test.bin", std::ios::in | std::ios::out | std::ios::binary | std::ios::trunc};
    std::cerr << "open: "<<  fs.is_open()
              << " good: " << fs.good()
              << " tellg: "<< fs.tellg()
              << " tellp: " << fs.tellp() 
              << std::endl;
    
    // writes "12" in binary
    fs.write("123", 2);

    std::cerr << "open: "<<  fs.is_open()
              << " good: " << fs.good()
              << " tellg: "<< fs.tellg()
              << " tellp: " << fs.tellp() 
              << std::endl;

    return 0;
}

印刷

open: 1 good: 1 tellg: 0 tellp: 0
open: 1 good: 1 tellg: 2 tellp: 2

为什么会 tellg() 因为我没有执行任何读取，所以 tellg() 不应该