The usual type conversions work for function types just as well as they work for non-function types: pkg1.PkgApiCall(SomeFuncType(x)) solved How can I convert function types with the same signature?
Delete the ‘s’ from the URL when you try to access your app, that’s all it takes. Just make sure you start the Go web server in normal (HTTP) mode. The HTTPS layer is added by the Heroku platform, but your app is still available via both HTTP and HTTPS protocol. So for example if … Read more
Problem Your first version has a synchronisation bug, which manifests itself as a data race: $ go run -race main.go 0 (PrintAddr): 0xc0000b4018 0 (PrintAddr): 0xc0000c2120 ================== WARNING: DATA RACE Write at 0x00c0000b4018 by main goroutine: main.main() redacted/main.go:29 +0x1e5 Previous read at 0x00c0000b4018 by goroutine 7: main.(*User).PrintAddr() redacted/main.go:19 +0x44 Goroutine 7 (finished) created at: main.main() … Read more
Introduction When dealing with functions, it is important to understand how to convert between different types of functions with the same signature. This is especially important when dealing with different programming languages, as the syntax and conventions for each language can be quite different. In this article, we will discuss how to convert between different … Read more
Introduction Heroku is a popular cloud platform for hosting web applications. It is a great platform for hosting Golang applications, but it can be tricky to serve them over HTTP instead of HTTPS. In this article, we will discuss how to serve a Golang app on Heroku using HTTP instead of HTTPS. We will cover … Read more
Those two lines in your main function shadow your global variable declaration: optQuit := getopt.BoolLong(“quit”, 0, “Help”) optRun := getopt.BoolLong(“run”, ‘r’, “Help”) If you only use them, to get a nice usage, why not create a usage function yourself? If you insist on using getopt just to create a usage, do _ = getopt.BoolLong(“quit”, 0, … Read more
on linux go version 1.15.2, i run below code and it spawns a new process that does not die with main. package main import ( “log” “os” “os/exec” ) func main() { cmd := exec.Command(“go”, “run”, “./d”) cmd.Stdin = os.Stdin cmd.Stdout = os.Stdout cmd.Stderr = os.Stderr log.Printf(“Running command and waiting for it to finish…”) err … Read more
You are using a pointer receiver for the method QueryPart. From the docs: Methods with pointer receivers can modify the value to which the receiver points So you will need to call the method on the object itself, something similar to this: contract := SmartContract{} contract.QueryPart(ctx) Or to call it directly remove the receiver (convert … Read more
You likely want to use the golang.org/x/net/html package. It’s not in the Go standard packages, but instead in the Go Sub-repositories. (The sub-repositories are part of the Go Project but outside the main Go tree. They are developed under looser compatibility requirements than the Go core.) There is an example in that documentation that may … Read more
However, running either of them gives an error saying: package hello_world is not in GOROOT (/usr/local/go/src/hello_world) You haven’t actually said what you’re doing to provoke this error, but it sounds like you’re almost certainly running go run hello_world. Once you’ve build an executable, Go (the language) and go (the command) are no longer involved. Binaries … Read more
What you did is clean and fast enough. What you could improve on it is to pre-allocate the slice and fill it using a for.. range loop like this: s := make([]int, 5) for i := range s { s[i] = rand.Intn(100) } The math/rand package also has a rand.Read() function which fills a slice … Read more
package main import “fmt” func main() { //create a map m := map[int64]int64{512: 8, 513: 9, 234: 9, 392: 0} //create a slice to hold required values s := make([][]int64, 0) //range over map `m` to append to slice `s` for k, v := range m { // append each element, with a new slice … Read more
Why is unmarshaling into a pointer variable not possible? It is possible. In fact, it’s required. Unmarshaling to a non-pointer is not possible. json: Unmarshal(nil *main.configuration) This error isn’t saying you can’t unmarshal to a pointer, it’s saying you can’t unmarshal to a nil pointer. The pointer must point to a valid (probably zero-value) variable. … Read more
An empty interface isn’t an actual type, it’s basically something that matches anything. As stated in the comments, a pointer to an empty interface doesn’t really make sense as a pointer already matches an empty interface since everything matches an empty interface. To make your code work, you should remove the interface wrapper around your … Read more
I found the answer with the help of a fellow Gopher from the community. The line of code containing srv.ListenAndServe() is a blocking line of code causing the log after this line of code not to happen. In my original code I demonstrated in my earlier blog I had this log in front of the … Read more