One lesson I learnt from reading std::variant implementation is that union in C++ can have complicated structure. Before, I thought we should only use union in this way: union U { int a; c...

I got quite confused the first time I read vector implementation. After a few minutes’ struggle, I realized that there are two implementations: the general vector and the specialized vector<boo&...

std::unordered_set Both unordered_set and unordered_map use an internal __hash_table object, so it suffices to only talk about how hash table works in C++. The basic structure looks like diagram ...

I use SSH almost every work day, but never thought about how it works exactly until one day I got an error message Permission denied (publickey) when trying to git clone a repo. This post documents...

pg_repack What locks used https://github.com/reorg/pg_repack/blob/306b0d4f7f86e807498ac00baec89ecd33411398/bin/pg_repack.c#L1599 How to clean up things DROP EXTENSION IF EXISTS pg_repack CASCAD...

Semgrep is a cool project. Command line entry is here. A few comment commands # scan a doc to test patthen matching semgrep scan -l yaml -e '<pattern_to_test>' <file_name> # Sometime...

Aarch64 is just arm64. The instruction set used in aarch64 is called A64. Procedure Call Standard (PCS) The ARM standard has a clear description of PCS. The first few parameters should be loa...

ECMAScript standard ECMAScript 5 (EC5) came out in 2009 ECMAScript 6 (EC6) came out in 2015. Meanwhile, the committee decided to use year to version the standard, so EC6 is also called EC2015...

Golang 1.7 has a DNS problem of resolving hosts like **.local. This is important in kubernetes. So a fix is raised and released in Golang 1.7.1. When testing goreplay, you should not port forward ...

As a newbie to Golang, I am quite impressed by the flexibility of global variables inside Golang. Below simple C program fails to compile. #include <stdio.h> int foo() { return 5; } int a = ...