如何缓缓执行可能返回错误的函数？

Question

Most cleanup functions, especially those related to the IO operations, return an error, and normally we'd prefer to defer their execution in case if we'd not forget to call them when we're done with acquired resources. For example, at some point in the code we might write something like this:

var r *SomeResource
var err error
if r, err = Open(/* parameters */); err != nil {
    return nil, err
}
defer r.Close() // This might return an error

It seems that if Close function returns an error, it'll be ignored. How can we gently process the returned error from such a function?

Answer 1

Using defer with a func() {}() like so.

var r *SomeResource
var err error
if r, err = Open(/* parameters */); err != nil {
    return nil, err
}
defer func() {
    if err = r.Close(); err != nil {
        fmt.Printf("ERROR: %v", err)
    }
}()