Sockets
PHP Manual

Predefined Constants

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.

AF_UNIX (integer)
AF_INET (integer)
AF_INET6 (integer)
Only available if compiled with IPv6 support.
SOCK_STREAM (integer)
SOCK_DGRAM (integer)
SOCK_RAW (integer)
SOCK_SEQPACKET (integer)
SOCK_RDM (integer)
MSG_OOB (integer)
MSG_WAITALL (integer)
MSG_PEEK (integer)
MSG_DONTROUTE (integer)
MSG_EOR (integer)
Not available on Windows platforms.
MSG_EOF (integer)
Not available on Windows platforms.
SO_DEBUG (integer)
SO_REUSEADDR (integer)
SO_REUSEPORT (integer)
This constant is only available in PHP 5.4.10 or later on platforms that support the SO_REUSEPORT socket option: this includes macOS and FreeBSD, but does not include Linux or Windows.
SO_KEEPALIVE (integer)
SO_DONTROUTE (integer)
SO_LINGER (integer)
SO_BROADCAST (integer)
SO_OOBINLINE (integer)
SO_SNDBUF (integer)
SO_RCVBUF (integer)
SO_SNDLOWAT (integer)
SO_RCVLOWAT (integer)
SO_SNDTIMEO (integer)
SO_RCVTIMEO (integer)
SO_TYPE (integer)
SO_ERROR (integer)
TCP_NODELAY (integer)
Used to disable Nagle TCP algorithm. Added in PHP 5.2.7.
SOL_SOCKET (integer)
PHP_NORMAL_READ (integer)
PHP_BINARY_READ (integer)
SOL_TCP (integer)
SOL_UDP (integer)

The following constants are defined under Windows and UNIX-like platforms. Each constant is only defined if their equal is available on the platform.

SOCKET_EINTR (integer)
Interrupted system call.
SOCKET_EBADF (integer)
Bad file number.
SOCKET_EACCES (integer)
Permission denied.
SOCKET_EFAULT (integer)
Bad address.
SOCKET_EINVAL (integer)
Invalid argument.
SOCKET_EMFILE (integer)
Too many open files.
SOCKET_ENAMETOOLONG (integer)
File name too long.
SOCKET_ENOTEMPTY (integer)
Directory not empty.
SOCKET_ELOOP (integer)
Too many symbolic links encountered.
SOCKET_EWOULDBLOCK (integer)
Operation would block.
SOCKET_EREMOTE (integer)
Object is remote.
SOCKET_EUSERS (integer)
Too many users.
SOCKET_ENOTSOCK (integer)
Socket operation on non-socket.
SOCKET_EDESTADDRREQ (integer)
Destination address required.
SOCKET_EMSGSIZE (integer)
Message too long.
SOCKET_EPROTOTYPE (integer)
Protocol wrong type for socket.
SOCKET_EPROTONOSUPPORT (integer)
Protocol not supported.
SOCKET_ESOCKTNOSUPPORT (integer)
Socket type not supported.
SOCKET_EOPNOTSUPP (integer)
Operation not supported on transport endpoint.
SOCKET_EPFNOSUPPORT (integer)
Protocol family not supported.
SOCKET_EAFNOSUPPORT (integer)
Address family not supported by protocol.
SOCKET_EADDRNOTAVAIL (integer)
Cannot assign requested address.
SOCKET_ENETDOWN (integer)
Network is down.
SOCKET_ENETUNREACH (integer)
Network is unreachable.
SOCKET_ENETRESET (integer)
Network dropped connection because of reset.
SOCKET_ECONNABORTED (integer)
Software caused connection abort.
SOCKET_ECONNRESET (integer)
Connection reset by peer.
SOCKET_ENOBUFS (integer)
No buffer space available.
SOCKET_EISCONN (integer)
Transport endpoint is already connected.
SOCKET_ENOTCONN (integer)
Transport endpoint is not connected.
SOCKET_ESHUTDOWN (integer)
Cannot send after transport endpoint shutdown.
SOCKET_ETIMEDOUT (integer)
Connection timed out.
SOCKET_ECONNREFUSED (integer)
Connection refused.
SOCKET_EHOSTDOWN (integer)
Host is down.
SOCKET_EHOSTUNREACH (integer)
No route to host.
SOCKET_EALREADY (integer)
Operation already in progress.
SOCKET_EINPROGRESS (integer)
Operation now in progress.

The following constants are only defined under Windows.

SOCKET_ENOPROTOOPT (integer)
SOCKET_EADDRINUSE (integer)
SOCKET_ETOOMYREFS (integer)
SOCKET_EPROCLIM (integer)
SOCKET_EDUOT (integer)
SOCKET_ESTALE (integer)
SOCKET_EDISCON (integer)
SOCKET_SYSNOTREADY (integer)
SOCKET_VERNOTSUPPORTED (integer)
SOCKET_NOTINITIALISED (integer)
SOCKET_HOST_NOT_FOUND (integer)
SOCKET_TRY_AGAIN (integer)
SOCKET_NO_RECOVERY (integer)
SOCKET_NO_DATA (integer)
SOCKET_NO_ADDRESS (integer)

The following constants are only available on UNIX-like platforms. Each constant is only defined if their equal is available on the platform.

SOCKET_EPERM (integer)
Operation not permitted.
SOCKET_ENOENT (integer)
No such file or directory.
SOCKET_EIO (integer)
I/O error.
SOCKET_ENXIO (integer)
No such device or address.
SOCKET_E2BIG (integer)
Arg list too long.
SOCKET_EAGAIN (integer)
Try again.
SOCKET_ENOMEM (integer)
Out of memory.
SOCKET_ENOTBLK (integer)
Block device required.
SOCKET_EBUSY (integer)
Device or resource busy.
SOCKET_EEXIST (integer)
File exists.
SOCKET_EXDEV (integer)
Cross-device link.
SOCKET_ENODEV (integer)
No such device.
SOCKET_ENOTDIR (integer)
Not a directory.
SOCKET_EISDIR (integer)
Is a directory.
SOCKET_ENFILE (integer)
File table overflow.
SOCKET_ENOTTY (integer)
Not a typewriter.
SOCKET_ENOSPC (integer)
No space left on device.
SOCKET_ESPIPE (integer)
Illegal seek.
SOCKET_EROFS (integer)
Read-only file system.
Too many links.
SOCKET_EPIPE (integer)
Broken pipe.
SOCKET_ENOLCK (integer)
No record locks available.
SOCKET_ENOSYS (integer)
Function not implemented.
SOCKET_ENOMSG (integer)
No message of desired type.
SOCKET_EIDRM (integer)
Identifier removed.
SOCKET_ECHRNG (integer)
Channel number out of range.
SOCKET_EL2NSYNC (integer)
Level 2 not synchronized.
SOCKET_EL3HLT (integer)
Level 3 halted.
SOCKET_EL3RST (integer)
Level 3 reset.
SOCKET_ELNRNG (integer)
Link number out of range.
SOCKET_EUNATCH (integer)
Protocol driver not attached.
SOCKET_ENOCSI (integer)
No CSI structure available.
SOCKET_EL2HLT (integer)
Level 2 halted.
SOCKET_EBADE (integer)
Invalid exchange.
SOCKET_EBADR (integer)
Invalid request descriptor.
SOCKET_EXFULL (integer)
Exchange full.
SOCKET_ENOANO (integer)
No anode.
SOCKET_EBADRQC (integer)
Invalid request code.
SOCKET_EBADSLT (integer)
Invalid slot.
SOCKET_ENOSTR (integer)
Device not a stream.
SOCKET_ENODATA (integer)
No data available.
SOCKET_ETIME (integer)
Timer expired.
SOCKET_ENOSR (integer)
Out of streams resources.
SOCKET_ENONET (integer)
Machine is not on the network.
Link has been severed.
SOCKET_EADV (integer)
Advertise error.
SOCKET_ESRMNT (integer)
Srmount error.
SOCKET_ECOMM (integer)
Communication error on send.
SOCKET_EPROTO (integer)
Protocol error.
SOCKET_EMULTIHOP (integer)
Multihop attempted.
SOCKET_EBADMSG (integer)
Not a data message.
SOCKET_ENOTUNIQ (integer)
Name not unique on network.
SOCKET_EBADFD (integer)
File descriptor in bad state.
SOCKET_EREMCHG (integer)
Remote address changed.
SOCKET_ERESTART (integer)
Interrupted system call should be restarted.
SOCKET_ESTRPIPE (integer)
Streams pipe error.
SOCKET_EPROTOOPT (integer)
Protocol not available.
SOCKET_ADDRINUSE (integer)
Address already in use.
SOCKET_ETOOMANYREFS (integer)
Too many references: cannot splice.
SOCKET_EISNAM (integer)
Is a named type file.
SOCKET_EREMOTEIO (integer)
Remote I/O error.
SOCKET_EDQUOT (integer)
Quota exceeded.
SOCKET_ENOMEDIUM (integer)
No medium found.
SOCKET_EMEDIUMTYPE (integer)
Wrong medium type.

Sockets
PHP Manual