| Value | Meaning |
|---|---|
| ALOOPER_EVENT_INPUT1 | The file descriptor is available for read operations. |
| ALOOPER_EVENT_OUTPUT2 | The file descriptor is available for write operations. |
| ALOOPER_EVENT_ERROR4 | The file descriptor has encountered an error condition. The looper always sends notifications about errors; it is not necessary to specify this event flag in the requested event set. |
| ALOOPER_EVENT_HANGUP8 | The file descriptor was hung up. For example, indicates that the remote end of a pipe or socket was closed. The looper always sends notifications about hangups; it is not necessary to specify this event flag in the requested event set. |
| ALOOPER_EVENT_INVALID16 | The file descriptor is invalid. For example, the file descriptor was closed prematurely. The looper always sends notifications about invalid file descriptors; it is not necessary to specify this event flag in the requested event set. |
Flags for file descriptor events that a looper can monitor.
These flag bits can be combined to monitor multiple events at once.