Error Handling

[Rich]

In most of my code I create a function to handle errors. looks something like this:

func errorHandle(err error, str string, ex bool) {

     if err != nil {

          fmt.Printf("error: %s -- %v\n",str, err)

     }

     if ex {

        os.Exit(1)

     }

}

This cleans up my code:

    inFile, err := os.ReadFile("Mydata.txt")

    errorHandle(err,"read mydata.txt",true) // The true will exit

So you see that I can exit the program when there is an error, what I want to know is if it's possible to do the same thing inside a function, to where I don't exit the program but return from the function:

func OpenFile( filename string) []byte {

    inFile,err := os.ReadFile(filename)

    errReturn(err, "read "+filname,true)

When there is an error it would return from the OpenFile function,

[Axel Wagner]

No, that is not possible. Only a `return` statement can return.

You *can* unwind the stack, using `panic` or `runtime.GoExit` (which is what `t.Fatal` does) but it's a bad idea in general (and FTR, I'd also consider your function a bad idea, but that's none of my business).

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[Richard Masci]

You said: "and FTR, I'd also consider your function a bad idea, but that's none of my business" <- I'll be the first to say not all my ideas are good ones, maybe this one isn't? Thanks for your response.

[ben...@gmail.com]

I agree with Axel that a function like errReturn is a bad idea, though if Go updates/improves error handling, it's possible we'll get something like that (some of the error handling proposals have been similar to errReturn).

However, I don't see anything wrong with a function like Richard's errHandle(), *if it's at the top level in main*. I often have a function like this in main.go for CLIs. The signature might be:

inFile, err := os.ReadFile("Mydata.txt")

exitOnError(err, "cannot read file")

-Ben

[Harri L]

A package err2 helps you to implement the `errReturn` even though Go doesn't have macros or can return from the function enclosing the function checking the error.
Please see the playground that does exactly that:

https://go.dev/play/p/GvXFU1LbVvs

However, I recommend you to use `err2` with all of its power, i.e., automation. Could you look at the following playground? Even the error strings/messages are autogenerated from function names (yeah, localization, but in most cases, enough to start with). Declarative error handling helps to keep your code safe.

https://go.dev/play/p/6Ky5nMtqu4F

And yes, I'm the author of the err2.