The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
| Constant | Type | Changelog |
|---|---|---|
| MSG_IPC_NOWAIT | integer | |
| MSG_EAGAIN | integer | As of 5.2.0 |
| MSG_ENOMSG | integer | As of 5.2.0 |
| MSG_NOERROR | integer | |
| MSG_EXCEPT | integer |