Use the fmt.Fprintf function to write formatted data to the standard error output and wrap it in a new line. If it fails, an error message is returned.

Use the fmt.Fprintf function to write formatted data to the standard error output and wrap it in a new line. If it fails, an error message will be returned.

The standard error output is usually used to write error information when the program is running. You can Easily view and locate issues. In the Go language, you can use the fmt.Fprintf function to write formatted data to the standard error output and wrap it in new lines. The signature of this function is:

func Fprintf(w io.Writer, format string, a ...interface{}) (n int, err error)

Among them, w is an object that implements the io.Writer interface, format is the format string, and a is the parameter to be filled in the format string.

The following is a sample code that demonstrates how to use the fmt.Fprintf function to write error information to the standard error output:

package main

import (
    "fmt"
    "os"
)

func main() {
    err := someFunc()
    if err != nil {
        errMsg := fmt.Sprintf("Error occurred: %s", err.Error())
        _, _ = fmt.Fprintf(os.Stderr, errMsg+"
")
    }
}

func someFunc() error {
    // 模拟发生错误
    return fmt.Errorf("something went wrong")
}

The above sample code defines a function named someFunc, which The function returns an error. In the main function, call the someFunc function and save the returned error in the variable err. If err is not empty, format it as the error message errMsg, and use the fmt.Fprintf function to write it to the standard error output and wrap it in a new line.

Run the above code, you will see output similar to the following when the program is running:

Error occurred: something went wrong

If writing to the standard error output fails, the fmt.Fprintf function will return a non-empty Error err. In the above example code, we do not handle this error for simplicity. But in actual applications, the error can be further handled, such as logging or falling back to other error handling mechanisms.

Summary:
This article describes how to use the fmt.Fprintf function to write formatted data to the standard error output and wrap new lines. It can help us quickly locate and track error messages during program development. Remember to handle error return values ​​in your actual application and choose an appropriate error handling strategy.

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