Functions and Error Handling

Functions are the building blocks of Go programs. Go functions support multiple return values, named return values, variadic parameters, and first-class function values. Combined with Go's explicit error handling pattern, functions form the backbone of idiomatic Go code.

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Function Basics

Declaring a Function

func greet(name string) string {
    return "Hello, " + name
}

Multiple Parameters of the Same Type

func add(a, b int) int {
    return a + b
}

When consecutive parameters share a type, you only need to specify the type once.

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Multiple Return Values

Go functions can return multiple values — this is fundamental to the language:

func divide(a, b float64) (float64, error) {
    if b == 0 {
        return 0, fmt.Errorf("cannot divide by zero")
    }
    return a / b, nil
}

// Usage:
result, err := divide(10, 3)
if err != nil {
    log.Fatal(err)
}
fmt.Println(result)   // 3.3333...

Multiple return values are the foundation of Go's error handling pattern.

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Named Return Values