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 (int)
Socket address family of filesystem pathnames in the Unix Domain.
AF_INET (int)
Socket address family of IPv4 in the Internet Domain.
AF_INET6 (int)
Socket address family of IPv6 in the Internet Domain. Only available if compiled with IPv6 support.
AF_DIVERT (int)
Available as of PHP 8.3.0 (FreeBSD only)
SOCK_STREAM (int)
SOCK_DGRAM (int)
SOCK_RAW (int)
SOCK_SEQPACKET (int)
SOCK_RDM (int)
MSG_OOB (int)
MSG_WAITALL (int)
MSG_PEEK (int)
MSG_DONTROUTE (int)
MSG_EOR (int)
Not available on Windows platforms.
MSG_EOF (int)
Not available on Windows platforms.
MSG_ZEROCOPY (int)
Available as of PHP 8.2.0
SO_DEBUG (int)
SO_REUSEADDR (int)
SO_REUSEPORT (int)
This constant is only available on platforms that support the SO_REUSEPORT socket option: this includes Linux, macOS and *BSD, but does not include Windows.
SO_KEEPALIVE (int)
SO_DONTROUTE (int)
SO_LINGER (int)
SO_BROADCAST (int)
SO_OOBINLINE (int)
SO_SNDBUF (int)
SO_RCVBUF (int)
SO_SNDLOWAT (int)
SO_RCVLOWAT (int)
SO_SNDTIMEO (int)
SO_RCVTIMEO (int)
SO_TYPE (int)
SO_ERROR (int)
SO_ZEROCOPY (int)
Available as of PHP 8.2.0
TCP_NODELAY (int)
Used to disable Nagle TCP algorithm.
TCP_KEEPCNT (int)
Available as of PHP 8.2.0
TCP_KEEPIDLE (int)
Available as of PHP 8.2.0
TCP_KEEPINTVL (int)
Available as of PHP 8.2.0
TCP_KEEPALIVE (int)
Available as of PHP 8.2.0
TCP_NOTSENT_LOWAT (int)
Available as of PHP 8.2.0
SO_MARK (int)
Available as of PHP 8.1.0
Available as of PHP 8.1.0
SO_RTABLE (int)
Available as of PHP 8.2.0
SO_ACCEPTFILTER (int)
Available as of PHP 8.1.0
SO_DONTTRUNC (int)
Available as of PHP 8.1.0
SO_WANTMORE (int)
Available as of PHP 8.1.0
SO_INCOMING_CPU (int)
Available as of PHP 8.2.0
SO_MEMINFO (int)
Available as of PHP 8.2.0
SO_BPF_EXTENSIONS (int)
Available as of PHP 8.2.0
SO_SETFIB (int)
Available as of PHP 8.2.0
SO_ATTACH_REUSEPORT_CBPF (int)
Available as of PHP 8.3.0 (Linux only)
SO_DETACH_BPF (int)
Available as of PHP 8.3.0 (Linux only)
SO_DETACH_FILTER (int)
Available as of PHP 8.3.0 (Linux only)
SO_RERROR (int)
Available as of PHP 8.3.0 (NetBSD only)
SO_ZEROIZE (int)
Available as of PHP 8.3.0 (OpenBSD only)
SO_SPLICE (int)
Available as of PHP 8.3.0 (OpenBSD only)
SO_REUSEPORT_LB (int)
Available as of PHP 8.3.0 (FreeBSD only)
SOL_FILTER (int)
Available as of PHP 8.2.0
SOL_UDPLITE (int)
Available as of PHP 8.3.0
UDPLITE_RECV_CSCOV (int)
Available as of PHP 8.3.0
UDPLITE_SEND_CSCOV (int)
Available as of PHP 8.3.0
TCP_DEFER_ACCEPT (int)
Available as of PHP 8.1.0
TCP_CONGESTION (int)
Available as of PHP 8.2.0
TCP_QUICKACK (int)
Available as of PHP 8.3.0 (Linux only)
TCP_REPAIR (int)
Available as of PHP 8.3.0 (Linux only)
IP_DONTFRAG (int)
Available as of PHP 8.3.0 (FreeBSD only)
IP_MTU_DISCOVER (int)
Available as of PHP 8.3.0 (Linux only)
IP_PMTUDISC_DO (int)
Available as of PHP 8.3.0 (Linux only)
IP_PMTUDISC_DONT (int)
Available as of PHP 8.3.0 (Linux only)
IP_PMTUDISC_WANT (int)
Available as of PHP 8.3.0 (Linux only)
IP_PMTUDISC_PROBE (int)
Available as of PHP 8.3.0 (Linux only)
IP_PMTUDISC_INTERFACE (int)
Available as of PHP 8.3.0 (Linux only)
IP_PMTUDISC_OMIT (int)
Available as of PHP 8.3.0 (Linux only)
IP_BIND_ADDRESS_NO_PORT (int)
Available as of PHP 8.3.0 (Linux only)
SOL_SOCKET (int)
PHP_NORMAL_READ (int)
PHP_BINARY_READ (int)
SOL_TCP (int)
SOL_UDP (int)

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

The following constants are only defined under Windows.

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

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 (int)
Operation not permitted.
SOCKET_ENOENT (int)
No such file or directory.
SOCKET_EIO (int)
I/O error.
SOCKET_ENXIO (int)
No such device or address.
SOCKET_E2BIG (int)
Arg list too long.
SOCKET_EAGAIN (int)
Try again.
SOCKET_ENOMEM (int)
Out of memory.
SOCKET_ENOTBLK (int)
Block device required.
SOCKET_EBUSY (int)
Device or resource busy.
SOCKET_EEXIST (int)
File exists.
SOCKET_EXDEV (int)
Cross-device link.
SOCKET_ENODEV (int)
No such device.
SOCKET_ENOTDIR (int)
Not a directory.
SOCKET_EISDIR (int)
Is a directory.
SOCKET_ENFILE (int)
File table overflow.
SOCKET_ENOTTY (int)
Not a typewriter.
SOCKET_ENOSPC (int)
No space left on device.
SOCKET_ESPIPE (int)
Illegal seek.
SOCKET_EROFS (int)
Read-only file system.
Too many links.
SOCKET_EPIPE (int)
Broken pipe.
SOCKET_ENOLCK (int)
No record locks available.
SOCKET_ENOSYS (int)
Function not implemented.
SOCKET_ENOMSG (int)
No message of desired type.
SOCKET_EIDRM (int)
Identifier removed.
SOCKET_ECHRNG (int)
Channel number out of range.
SOCKET_EL2NSYNC (int)
Level 2 not synchronized.
SOCKET_EL3HLT (int)
Level 3 halted.
SOCKET_EL3RST (int)
Level 3 reset.
SOCKET_ELNRNG (int)
Link number out of range.
SOCKET_EUNATCH (int)
Protocol driver not attached.
SOCKET_ENOCSI (int)
No CSI structure available.
SOCKET_EL2HLT (int)
Level 2 halted.
SOCKET_EBADE (int)
Invalid exchange.
SOCKET_EBADR (int)
Invalid request descriptor.
SOCKET_EXFULL (int)
Exchange full.
SOCKET_ENOANO (int)
No anode.
SOCKET_EBADRQC (int)
Invalid request code.
SOCKET_EBADSLT (int)
Invalid slot.
SOCKET_ENOSTR (int)
Device not a stream.
SOCKET_ENODATA (int)
No data available.
SOCKET_ETIME (int)
Timer expired.
SOCKET_ENOSR (int)
Out of streams resources.
SOCKET_ENONET (int)
Machine is not on the network.
Link has been severed.
SOCKET_EADV (int)
Advertise error.
SOCKET_ESRMNT (int)
Srmount error.
SOCKET_ECOMM (int)
Communication error on send.
SOCKET_EPROTO (int)
Protocol error.
SOCKET_EMULTIHOP (int)
Multihop attempted.
SOCKET_EBADMSG (int)
Not a data message.
SOCKET_ENOTUNIQ (int)
Name not unique on network.
SOCKET_EBADFD (int)
File descriptor in bad state.
SOCKET_EREMCHG (int)
Remote address changed.
SOCKET_ERESTART (int)
Interrupted system call should be restarted.
SOCKET_ESTRPIPE (int)
Streams pipe error.
SOCKET_EPROTOOPT (int)
Protocol not available.
SOCKET_ADDRINUSE (int)
Address already in use.
SOCKET_ETOOMANYREFS (int)
Too many references: cannot splice.
SOCKET_EISNAM (int)
Is a named type file.
SOCKET_EREMOTEIO (int)
Remote I/O error.
SOCKET_EDQUOT (int)
Quota exceeded.
SOCKET_ENOMEDIUM (int)
No medium found.
SOCKET_EMEDIUMTYPE (int)
Wrong medium type.
SCM_RIGHTS (int)
Send or receive a set of open file descriptors from another process.
SCM_CREDENTIALS (int)
SCM_CREDS (int)
Available as of PHP 8.2.0
SCM_CREDS2 (int)
Available as of PHP 8.2.0
LOCAL_CREDS (int)
Available as of PHP 8.2.0
LOCAL_CREDS_PERSISTENT (int)
Available as of PHP 8.2.0
SKF_AD_OFF (int)
Available as of PHP 8.2.0
SKF_AD_PROTOCOL (int)
Available as of PHP 8.2.0
SKF_AD_PKTTYPE (int)
Available as of PHP 8.2.0
SKF_AD_IFINDEX (int)
Available as of PHP 8.2.0
SKF_AD_NLATTR (int)
Available as of PHP 8.2.0
SKF_AD_NLATTR_NEST (int)
Available as of PHP 8.2.0
SKF_AD_MARK (int)
Available as of PHP 8.2.0
SKF_AD_QUEUE (int)
Available as of PHP 8.2.0
SKF_AD_HATYPE (int)
Available as of PHP 8.2.0
SKF_AD_RXHASH (int)
Available as of PHP 8.2.0
SKF_AD_CPU (int)
Available as of PHP 8.2.0
SKF_AD_ALU_XOR_X (int)
Available as of PHP 8.2.0
SKF_AD_VLAN_TAG (int)
Available as of PHP 8.2.0
SKF_AD_VLAN_TAG_PRESENT (int)
Available as of PHP 8.2.0
SKF_AD_PAY_OFFSET (int)
Available as of PHP 8.2.0
SKF_AD_RANDOM (int)
Available as of PHP 8.2.0
SKF_AD_VLAN_TPID (int)
Available as of PHP 8.2.0
SKF_AD_MAX (int)
Available as of PHP 8.2.0
AI_ADDRCONFIG (int)
AI_ALL (int)
AI_CANONIDN (int)
AI_CANONNAME (int)
AI_IDN (int)
AI_NUMERICHOST (int)
AI_NUMERICSERV (int)
AI_PASSIVE (int)
AI_V4MAPPED (int)
FIL_ATTACH (int)
FIL_DETACH (int)
IPPROTO_IP (int)
IPPROTO_IPV6 (int)
IPV6_HOPLIMIT (int)
IPV6_MULTICAST_HOPS (int)
IPV6_MULTICAST_IF (int)
IPV6_MULTICAST_LOOP (int)
IPV6_PKTINFO (int)
IPV6_RECVHOPLIMIT (int)
IPV6_RECVPKTINFO (int)
IPV6_RECVTCLASS (int)
IPV6_TCLASS (int)
IPV6_UNICAST_HOPS (int)
IPV6_V6ONLY (int)
IP_MULTICAST_IF (int)
IP_MULTICAST_LOOP (int)
IP_MULTICAST_TTL (int)
MCAST_BLOCK_SOURCE (int)
MCAST_JOIN_GROUP (int)
MCAST_JOIN_SOURCE_GROUP (int)
MCAST_LEAVE_GROUP (int)
MCAST_LEAVE_SOURCE_GROUP (int)
MCAST_UNBLOCK_SOURCE (int)
MSG_CMSG_CLOEXEC (int)
MSG_CONFIRM (int)
MSG_CTRUNC (int)
MSG_DONTWAIT (int)
MSG_ERRQUEUE (int)
MSG_MORE (int)
MSG_NOSIGNAL (int)
MSG_TRUNC (int)
MSG_WAITFORONE (int)
SOL_LOCAL (int)
SOMAXCONN (int)
SO_BINDTODEVICE (int)
SO_FAMILY (int)
SO_LABEL (int)
SO_LISTENQLEN (int)
SO_LISTENQLIMIT (int)
SO_PASSCRED (int)
SO_PEERLABEL (int)