오늘도 나는

    import os
     
    with open('logfile.txt', 'rb') as f:
    f.seek(-2, os.SEEK_END)
    while f.read(1) != b'\n':
    f.seek(-2, os.SEEK_CUR)
    print(f.readline().decode())

출처: https://www.quora.com/How-can-I-read-the-last-line-from-a-log-file-in-Python

해당 에러를 매뉴얼하게 고치기 위해서는 /usr/include/bits/floatn.h 파일을 조금 수정하면 된다.

original code

#if (defined __x86_64__                                                 \
     ? __GNUC_PREREQ (4, 3)                                             \
     : (defined __GNU__ ? __GNUC_PREREQ (4, 5) : __GNUC_PREREQ (4, 4)))
# define __HAVE_FLOAT128 1
#else
# define __HAVE_FLOAT128 0
#endif

modified code

#if (defined __x86_64__                                                 \
     ? __GNUC_PREREQ (4, 3)                                             \
     : (defined __GNU__ ? __GNUC_PREREQ (4, 5) : __GNUC_PREREQ (4, 4)))
//# define __HAVE_FLOAT128 1
//#else
# define __HAVE_FLOAT128 0
#endif

Here is how I understood not just what virtual functions are, but why they're required:

Let's say you have these two classes:

class Animal { public: void eat() { std::cout << "I'm eating generic food."; } }; class Cat : public Animal { public: void eat() { std::cout << "I'm eating a rat."; } };

In your main function:

Animal *animal = new Animal; Cat *cat = new Cat; animal->eat(); // Outputs: "I'm eating generic food." cat->eat(); // Outputs: "I'm eating a rat."

So far so good, right? Animals eat generic food, cats eat rats, all without virtual.

Let's change it a little now so that eat() is called via an intermediate function (a trivial function just for this example):

// This can go at the top of the main.cpp file void func(Animal *xyz) { xyz->eat(); }

Now our main function is:

Animal *animal = new Animal; Cat *cat = new Cat; func(animal); // Outputs: "I'm eating generic food." func(cat); // Outputs: "I'm eating generic food."

Uh oh... we passed a Cat into func(), but it won't eat rats. Should you overload func() so it takes a Cat*? If you have to derive more animals from Animal they would all need their own func().

The solution is to make eat() from the Animal class a virtual function:

class Animal { public: virtual void eat() { std::cout << "I'm eating generic food."; } }; class Cat : public Animal { public: void eat() { std::cout << "I'm eating a rat."; } };

Main:

func(animal); // Outputs: "I'm eating generic food." func(cat); // Outputs: "I'm eating a rat."

Done.

https://stackoverflow.com/questions/2391679/why-do-we-need-virtual-functions-in-c

binding 과 관련된 일이다..필요하면 early binding/late binding 찾아봐

https://www.geeksforgeeks.org/virtual-function-cpp/