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  Understand unsafe in GoLang

Before going to understand unsafe package in GoLang, the first thing needs to talk about is the pointer in GoLang. If you have a background of C language, you must know what pointer means and its usage. With pointer, you are free to operate any data at memory level which means you have great power, but this means that you have great responsibility as well. That's why it might be considered unsafe in lots of cases. Take a look at a simple example of doubling an integer. package main import "fmt"...

   GOLANG,UNSAFE,ZERO-COPY     2020-03-14 23:18:00

  Behavior of defer function in named return function

In Go, there is a special concept of named return value in function where a returned value can have name. For example, below is a named function in Go. func returnNamed() (i int) { i = 1 return } When the function returns, the return value i will have a value of 1.  Also, Go has a concept of defer which will execute a function just before the calling function exits. This is similar to what finally block does in other languages such as Java. For example, a defer function can be func deferF...

   GOLANG,DEFER,NAMED RETURN,DIFFERENCE     2018-11-20 09:04:07

  Be careful about printing error as string in GoLang

In GoLang, we can format and produce string using fmt.Printf(), just like C, GoLang also supports format verbs like %s, %d which can be placeholder for different types of values. But please pay attention when printing error as string so that you will not fall into some trap. Let's first take an example code snippet and see what trap we are talking about. package main import "fmt" type A string func (a A) Error() string { return fmt.Sprintf("%s is an error", a) } func main() { a := A("hello...

   STACKOVERFLOW,GOLANG,FMT     2019-01-23 09:17:15

  Time to think about supporting max/min functions for integers in GoLang

Sometime back we wrote a post explaining why there is no max/min function support for integers in GoLang, one of the reasons is that no overloading is supported and the function name has been used for other numeric types float64. To solve this problem and make max/min function support integer as well, either GoLang should support overloading like in Java or the same set of functions need to be created in a different package other than standard math. These don't look like good options as overload...

   MIN,MAX,GENERICS,GOLANG     2021-07-24 03:14:42

  Foursquare : 20 million users and 2 billion check-ins

Yesterday was the Foursquare third annual 4sqDay celebration (Four - squared open four square, ie April 16), this mobile phone service site which is based on user location information confirmed that their users reached 20 million and there were two billion check-ins.Foursquare was founded in 2009 and it is a mobile phone service website based on the user location information .It encourages mobile phone users to share their current geographic location and other information with others. In co...

   Fpoursquare,Check-in,4sqDay     2012-04-17 13:39:14

  New function signal.NotifyContext in GoLang 1.16

os/signal package in GoLang may not be frequently used but it provides some good features like Shutdown() which can be used to gracefully shutdown a running HTTP server. func (srv *Server) Shutdown(ctx context.Context) error With this function, there is no need to use third party library to gracefully shutdown HTTP server. How is it being used? package main import ( "context" "fmt" "net/http" "os" "os/signal" "time" ) func main() { server := http.Server{ Addr: ":8080", } http.Handl...

   GOLANG,NOTIFYCONTEXT,GRACEFUL SHUTDOWN     2021-06-19 01:07:10

  How to Understand and Use nil in Golang Correctly?

In Golang, nil is a predefined identifier that carries different meanings in various contexts, but typically represents "none", "empty" or "zero value". It can be assigned to variables of pointer, slice, map, channel, function, and interface types. Understanding the significance of nil is crucial for writing robust Go programs, as mishandling nil can lead to unexpected issues. nil in Pointers In Go, pointers are a fundamental type that stores the memory address of a variable. When a pointer is d...

   FUNCTION,SLICE,MAP,CHANNEL,GOLANG,NIL     2024-01-05 05:19:40

  What is the use of empty struct in GoLang

In Go, an empty struct struct{} is a struct with no fields that may appear to be of little use, but in reality, it can be useful in certain situations and become a simple and efficient solution in code. As a semaphore or lock Because the empty struct has no fields, it can be conveniently used to implement some concurrency control functions, such as mutex locks, read-write locks. We can use chan struct{} to implement an unbuffered channel for controlling concurrent access. package main import ( ...

   GOLANG,EMPTY STRUCT     2024-04-05 23:54:03

  Why init() is not recommended in Go

golangci lint Currently, the unified CI's .golangci.yml includes the gochecknoinits checker: # golangci-lint v1.46.2 # https://golangci-lint.run/usage/linters linters: disable-all: true enable: ... - gochecknoinits # Checks that no init functions are present in Go code. ref: https://github.com/leighmcculloch/gochecknoinits ... If Go code uses the init() function, the following error will occur: # golangci-lint run foo/foo.go:3:1: don't use `init` function (gochecknoinits) func i...

   GOLANG,INIT(),SYNC.ONCE,PANIC     2024-05-10 07:46:18

  Ensuring Go Interface Implementation: A Quick Guide

Introduction Go's simplicity and power shine in its interface system, offering a clean way to define contracts between types. However, when it comes to checking whether a struct satisfies an interface, Go's static typing philosophy means there isn't a direct runtime check. In this concise guide, we'll explore practical methods, including some lesser-known tricks, to verify whether a struct implements an interface. Method 1: Type Assertion and a Dummy Method package main import "fmt" type MyInt...

   INTERFACE,GOLANG,IMPLEMENTS     2023-11-25 21:36:01

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