This is a bit long, but personally I prefer to use the standard C defines in my code.
<?php
define('ENOTSOCK', 88); /* Socket operation on non-socket */
define('EDESTADDRREQ', 89); /* Destination address required */
define('EMSGSIZE', 90); /* Message too long */
define('EPROTOTYPE', 91); /* Protocol wrong type for socket */
define('ENOPROTOOPT', 92); /* Protocol not available */
define('EPROTONOSUPPORT', 93); /* Protocol not supported */
define('ESOCKTNOSUPPORT', 94); /* Socket type not supported */
define('EOPNOTSUPP', 95); /* Operation not supported on transport endpoint */
define('EPFNOSUPPORT', 96); /* Protocol family not supported */
define('EAFNOSUPPORT', 97); /* Address family not supported by protocol */
define('EADDRINUSE', 98); /* Address already in use */
define('EADDRNOTAVAIL', 99); /* Cannot assign requested address */
define('ENETDOWN', 100); /* Network is down */
define('ENETUNREACH', 101); /* Network is unreachable */
define('ENETRESET', 102); /* Network dropped connection because of reset */
define('ECONNABORTED', 103); /* Software caused connection abort */
define('ECONNRESET', 104); /* Connection reset by peer */
define('ENOBUFS', 105); /* No buffer space available */
define('EISCONN', 106); /* Transport endpoint is already connected */
define('ENOTCONN', 107); /* Transport endpoint is not connected */
define('ESHUTDOWN', 108); /* Cannot send after transport endpoint shutdown */
define('ETOOMANYREFS', 109); /* Too many references: cannot splice */
define('ETIMEDOUT', 110); /* Connection timed out */
define('ECONNREFUSED', 111); /* Connection refused */
define('EHOSTDOWN', 112); /* Host is down */
define('EHOSTUNREACH', 113); /* No route to host */
define('EALREADY', 114); /* Operation already in progress */
define('EINPROGRESS', 115); /* Operation now in progress */
define('EREMOTEIO', 121); /* Remote I/O error */
define('ECANCELED', 125); /* Operation Canceled */
?>