Firstly, other than in the main module, an import should not have the side effect of spawning a new thread and then waiting for that thread in any way. Failing to abide by this restriction can lead to a deadlock if the spawned thread directly or indirectly attempts to import a module.
Secondly, all import attempts must be completed before the interpreter starts shutting itself down. This can be most easily achieved by only performing imports from non-daemon threads created through the threading module. Daemon threads and threads created directly with the thread module will require some other form of synchronization to ensure they do not attempt imports after system shutdown has commenced. Failure to abide by this restriction will lead to intermittent exceptions and crashes during interpreter shutdown (as the late imports attempt to access machinery which is no longer in a valid state).
// RegisterConn registers a network connection to be used // by inbound messages referring to the connection // with the registered connection's local and remote address. // Note: a connection does not need to be registered before // being sent in a message, but does need to be registered // to by the receiver of a message. If registration should be // automatic, register a listener instead.
Both vectors and deques provide a very similar interface and can be used for similar purposes, but internally both work in quite different ways: While vectors use a single array that needs to be occasionally reallocated for growth, the elements of a deque can be scattered in different chunks of storage, with the container keeping the necessary information internally to provide direct access to any of its elements in constant time and with a uniform sequential interface (through iterators). Therefore, deques are a little more complex internally than vectors, but this allows them to grow more efficiently under certain circumstances, especially with very long sequences, where reallocations become more expensive.
目前代码里有个小问题: ```go // CleanDir removes binary files under rundir in case they were not // accessed for more than CleanFileDelay nanoseconds. A last-cleaned // marker file is created so that the next verification is only done // after CleanFileDelay nanoseconds. func CleanDir(rundir string, now time.Time) error { cleanedfile := filepath.Join(rundir, "last-cleaned") cleanLine := now.Add(-CleanFileDelay) if info, err := os.Stat(cleanedfile); err == nil && info.ModTime().After(cleanLine) { // It's been cleaned recently. return nil } f, err := os.Create(cleanedfile) if err != nil { return err } _, err = f.Write([]byte(now.Format(time.RFC3339))) f.Close() if err != nil { return err }
// Look for expired files. d, err := os.Open(rundir) if err != nil { return err } infos, err := d.Readdir(-1) for _, info := range infos { atim := sysStat(info).Atim access := time.Unix(int64(atim.Sec), int64(atim.Nsec)) if access.Before(cleanLine) { os.Remove(filepath.Join(rundir, info.Name())) } } return nil }