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/

Error running Valgrind on Gentoo Linux: the strlen problem

add

source /vivado/settings64.sh/path

to ~/.profile file

powerline / fontawesome font 는 font폴더에 설치를 해야함

network dns는 resolv.conf 파일안에거를 수정해야되는데 이건 자꾸 재설정되니까 resolvconf command를 통해하거나 ifdown/ifup을 통해해야함

한글설정은 uim 설치한뒤 global settings에서 default input method를 byeoru로 바꿔야함

When use NVIDIA Graphic card, drivers for graphic card should not be upgraded. 

It would be better download driver through NVIDIA homepage directly and install after system upgrade. 

Xserver and Xorg-drivers must match with graphic card version. maybe downgrade?

Reinstall drivers for input devices (keyboard, mouse..) -> xf86-input-libinput

Virtualbox reinstall through virtualbox homepage. 

maybe it can done with emerge. but virtualbox version and qt version must match, so it can be messy. 

http://venividiwiki.ee.virginia.edu/mediawiki/index.php/DNNWeaver