Sockets unit

TCP/IP Sockets functionality unit.

This document describes the SOCKETS unit for Free Pascal. it was written for Linux by Michael Van Canneyt, and ported to Windows by Florian Klaempfl.

Classes and records

`in_addr`	record	General inet socket address.
`in6_addr`	record	General purpose IPV6 address.
`linger`	record	Record used in setsockopt.
`sockaddr`	record	Alias for TSockAddr record type.
`sockaddr_in`	record	Internet socket address record.
`sockaddr_in6`	record	Alias for .
`sockaddr_un`	record	Unix socket address record.
`TUnixSockAddr`	record	Alias for sockaddr_un.
`ucred`	record	User process credentials.

Procedures and functions

`Accept`	function	Accept a connection from a socket (deprecated).
`Bind`	function	Alias for fpBind.
`CloseSocket`	function	Closes a socket handle.
`Connect`	function	Open a connection to a server socket (deprecated).
`fpaccept`	function	Accept a connection from a socket.
`fpbind`	function	Bind a socket to an address.
`fpconnect`	function	Open a connection to a server socket.
`fpgetpeername`	function	Return the name (address) of the connected peer.
`fpgetsockname`	function	Return name of socket.
`fpgetsockopt`	function	Get current socket options.
`fplisten`	function	Listen for connections on a socket.
`fprecv`	function	Receive data on socket.
`fprecvfrom`	function	Receive data from an unconnected socket.
`fpsend`	function	Send data through socket.
`fpsendto`	function	Send data through an unconnected socket to an address.
`fpsetsockopt`	function	Set socket options.
`fpshutdown`	function	Close one end of full duplex connection.
`fpsocket`	function	Create new socket.
`fpsocketpair`	function	Create socket pair.
`HostAddrToStr`	function	Convert a host address to a string.
`HostAddrToStr6`	function	Convert a IPV6 host address to a string representation.
`HostToNet`	function	Convert a host address to a network address.
`htonl`	function	Convert long integer from host ordered to network ordered.
`htons`	function	Convert short integer from host ordered to network ordered.
`NetAddrIsPrivate`	function
`NetAddrIsPrivate6`	function
`NetAddrToStr`	function	Convert a network address to a string.
`NetAddrToStr6`	function	Convert a IPV6 network address to a string.
`NetToHost`	function	Convert a network address to a host address.
`NToHl`	function	Convert long integer from network ordered to host ordered.
`NToHs`	function	Convert short integer from network ordered to host ordered.
`ShortHostToNet`	function	Convert a host port number to a network port number.
`ShortNetToHost`	function	Convert a network port number to a host port number.
`Sock2File`	procedure	Convert socket to untyped file descriptors.
`Sock2Text`	procedure	Convert socket to text file descriptors.
`socketerror`	function	Contains the error code for the last socket operation.
`Str2UnixSockAddr`	procedure	Convert path to .
`StrToHostAddr`	function	Convert a string to a host address.
`StrToHostAddr6`	function	Convert a string to a IPV6 host address.
`StrToNetAddr`	function	Convert a string to a network address.
`StrToNetAddr6`	function	Convert a string to a IPV6 network address.
`TryStrToHostAddr`	function	Try to convert a string to an IPV4 address.
`TryStrToHostAddr6`	function	Try to convert a string to an IPV6 address.
`TryStrToNetAddr`	function

Types

`pin_addr`	type	Pointer to in_addr record.
`pin6_addr`	type	Pointer to .
`PIn6Addr`	type	Pointer to in6_addr type.
`PInAddr`	type	Alias for pin_addr.
`PInetSockAddr`	type	Pointer to .
`PInetSockAddr6`	type	Pointer to sockaddr_in6 type.
`plinger`	type	Pointer to linger type.
`psockaddr`	type	Pointer to .
`psockaddr_in`	type	Pointer to sockaddr_in.
`psockaddr_in6`	type	Pointer to .
`psockaddr_un`	type	Pointer to sockaddr_un type.
`PSockAddr6`	type	Pointer to TSockAddr6.
`Pucred`	type	Pointer to ucred.
`sa_family_t`	type	Address family type.
`TIn_addr`	type	Alias for in_addr record type.
`Tin6_addr`	type	Alias for .
`TIn6Addr`	type	Alias for in6_addr type.
`TInAddr`	type	Alias for in_addr record type.
`TInetSockAddr`	type	Alias for sockaddr_in.
`TInetSockAddr6`	type	Alias for sockaddr_in6.
`TLinger`	type	Alias for linger.
`TSockAddr`	type
`TSockAddr6`	type	Alias for sockaddr_in6/>.
`TSockArray`	type	Type returned by the call.
`Tsocket`	type	Alias for easy kylix porting.
`TSockLen`	type	Type to specify socket length in fpBind and fpConnect.
`TSockPairArray`	type	Array of sockets, used in call.

Constants

`AF_ALG`	constant	Address family: Algorithm sockets.
`AF_APPLETALK`	constant	Address family Appletalk DDP.
`AF_ASH`	constant	Address family: Ash.
`AF_ATMPVC`	constant	Address family: ATM PVCs.
`AF_ATMSVC`	constant	Address family: ATM SVCs.
`AF_AX25`	constant	Address family Amateur Radio AX.25.
`AF_BLUETOOTH`	constant	Address family: Bluetooth sockets.
`AF_BRIDGE`	constant	Address family Multiprotocol bridge.
`AF_CAIF`	constant	Address family: CAIF (Application CPU interface) sockets.
`AF_CAN`	constant	Address family: CAN (Controller Area Network) sockets.
`AF_DECnet`	constant	Address family: Reserved for DECnet project.
`AF_ECONET`	constant	Address family: Acorn Econet.
`AF_IB`	constant	Address family: IB (Infiniband) sockets.
`AF_IEEE802154`	constant	Address family: IEEE802154 sockets.
`AF_INET`	constant	Address family Internet IP Protocol.
`AF_INET6`	constant	Address family IP version 6.
`AF_IPX`	constant	Address family Novell IPX.
`AF_IRDA`	constant	Address family: IRDA sockets.
`AF_ISDN`	constant	Address family: ?
`AF_IUCV`	constant	Address family: IUCV (Inter User Communication Vehicle) sockets.
`AF_KCM`	constant	Address family: KCM (Kernel Connection Multiplexor) sockets.
`AF_KEY`	constant	Address family: PF_KEY key management API.
`AF_LLC`	constant	Address family: Linux LLC.
`AF_LOCAL`	constant	Address family: Unix socket.
`AF_MAX`	constant	Address family Maximum value.
`AF_MPLS`	constant	Address family: MPLS (Multiprotocol Label Switching) sockets.
`AF_NETBEUI`	constant	Address family: Reserved for 802.2LLC project.
`AF_NETLINK`	constant	Address family: ?
`AF_NETROM`	constant	Address family Amateur radio NetROM.
`AF_NFC`	constant	Address family: NFC (Near Field Communication) sockets.
`AF_PACKET`	constant	Address family: Packet family.
`AF_PHONET`	constant	Address family: Phonet sockets.
`AF_PPPOX`	constant	Address family: PPPoX sockets.
`AF_QIPCRTR`	constant	Address family: QIPCRTR (Qualcomm IPC Router) sockets.
`AF_RDS`	constant	Address Family: RDS (Reliable Datagram Sockets) sockets.
`AF_ROSE`	constant	Address family: Amateur Radio X.25 PLP.
`AF_ROUTE`	constant	Address family: Alias to emulate 4.4BSD.
`AF_RXRPC`	constant	Address family: RxRPC sockets.
`AF_SECURITY`	constant	Address family: Security callback pseudo AF.
`AF_SMC`	constant	Address family: SMC (Shared Memory Communication) sockets.
`AF_SNA`	constant	Address family: Linux SNA project.
`AF_TIPC`	constant	Address family: TIPC sockets.
`AF_UNIX`	constant	Address family Unix domain sockets.
`AF_UNSPEC`	constant	Address family Not specified.
`AF_VSOCK`	constant	Address family: VSOCK (hypervisor) sockets.
`AF_WANPIPE`	constant	Address family: Wanpipe API Sockets.
`AF_X25`	constant	Address family Reserved for X.25 project.
`AF_XDP`	constant	Address family: XDP (Express Data Path) sockets.
`EADDRINUSE`	constant
`EADDRNOTAVAIL`	constant
`EAFNOSUPPORT`	constant
`EALREADY`	constant
`ECONNABORTED`	constant
`ECONNREFUSED`	constant
`ECONNRESET`	constant
`EDESTADDRREQ`	constant
`EDQUOT`	constant
`EHOSTDOWN`	constant
`EHOSTUNREACH`	constant
`EINPROGRESS`	constant
`EINTR`	constant
`EISCONN`	constant
`ELOOP`	constant
`EMSGSIZE`	constant
`ENAMETOOLONG`	constant
`ENETDOWN`	constant
`ENETRESET`	constant
`ENETUNREACH`	constant
`ENOBUFS`	constant
`ENOPROTOOPT`	constant
`ENOTCONN`	constant
`ENOTEMPTY`	constant
`ENOTSOCK`	constant
`EOPNOTSUPP`	constant
`EPFNOSUPPORT`	constant
`EPROTONOSUPPORT`	constant
`EPROTOTYPE`	constant
`EREMOTE`	constant
`ESHUTDOWN`	constant
`EsockADDRINUSE`	constant	Error number when socket address is already in use.
`EsockEACCESS`	constant	Access forbidden error.
`EsockEBADF`	constant	Alias: bad file descriptor.
`EsockEFAULT`	constant	Alias: an error occurred.
`EsockEINTR`	constant	Alias : operation interrupted.
`EsockEINVAL`	constant	Alias: Invalid value specified.
`EsockEMFILE`	constant	Error code ?
`EsockEMSGSIZE`	constant	Wrong message size error.
`EsockENOBUFS`	constant	No buffer space available error.
`EsockENOTCONN`	constant	Not connected error.
`EsockENOTSOCK`	constant	File descriptor is not a socket error.
`EsockEPROTONOSUPPORT`	constant	Protocol not supported error.
`EsockEWOULDBLOCK`	constant	Operation would block error.
`ESOCKTNOSUPPORT`	constant
`ESTALE`	constant
`ETIMEDOUT`	constant
`ETOOMANYREFS`	constant
`EUSERS`	constant
`EWOULDBLOCK`	constant
`INADDR_ANY`	constant	A bitmask matching any IP address on the local machine.
`INADDR_NONE`	constant	A bitmask matching no valid IP address.
`IP_ADD_MEMBERSHIP`	constant	add an IP group membership.
`IP_ADD_SOURCE_MEMBERSHIP`	constant	join source group.
`IP_BLOCK_SOURCE`	constant	block data from source.
`IP_DEFAULT_MULTICAST_LOOP`	constant	Undocumented ?
`IP_DEFAULT_MULTICAST_TTL`	constant	Undocumented ?
`IP_DROP_MEMBERSHIP`	constant	drop an IP group membership.
`IP_DROP_SOURCE_MEMBERSHIP`	constant	leave source group.
`IP_HDRINCL`	constant	Header is included with data.
`IP_MAX_MEMBERSHIPS`	constant	Maximum group memberships for multicast messages.
`IP_MSFILTER`	constant	Undocumented ?
`IP_MTU_DISCOVER`	constant	Undocumented ?
`IP_MULTICAST_IF`	constant	set/get IP multicast i/f.
`IP_MULTICAST_LOOP`	constant	set/get IP multicast loopback.
`IP_MULTICAST_TTL`	constant	set/get IP multicast ttl.
`IP_OPTIONS`	constant	IP per-packet options.
`IP_PKTINFO`	constant	Undocumented ?
`IP_PKTOPTIONS`	constant	Undocumented ?
`IP_PMTUDISC`	constant	Undocumented ?
`IP_PMTUDISC_DO`	constant	Always DF.
`IP_PMTUDISC_DONT`	constant	Never send DF frames.
`IP_PMTUDISC_WANT`	constant	Use per route hints.
`IP_RECVERR`	constant	Undocumented ?
`IP_RECVOPTS`	constant	Receive all IP options w/datagram.
`IP_RECVRETOPTS`	constant	Receive IP options for response.
`IP_RECVTOS`	constant	Undocumented ?
`IP_RECVTTL`	constant	Undocumented ?
`IP_RETOPTS`	constant	Set/get IP per-packet options.
`IP_ROUTER_ALERT`	constant	Undocumented ?
`IP_TOS`	constant	IP type of service and precedence.
`IP_TTL`	constant	IP time to live.
`IP_UNBLOCK_SOURCE`	constant	unblock data from source.
`IPPROTO_AH`	constant	authentication header.
`IPPROTO_COMP`	constant	Compression Header Protocol.
`IPPROTO_DSTOPTS`	constant	IPv6 destination options.
`IPPROTO_EGP`	constant	Exterior Gateway Protocol.
`IPPROTO_ENCAP`	constant	Encapsulation Header.
`IPPROTO_ESP`	constant	encapsulating security payload.
`IPPROTO_FRAGMENT`	constant	IPv6 fragmentation header.
`IPPROTO_GRE`	constant	General Routing Encapsulation.
`IPPROTO_HOPOPTS`	constant	IPv6 Hop-by-Hop options.
`IPPROTO_ICMP`	constant	Internet Control Message Protocol.
`IPPROTO_ICMPV6`	constant	ICMPv6.
`IPPROTO_IDP`	constant	XNS IDP protocol.
`IPPROTO_IGMP`	constant	Internet Group Management Protocol.
`IPPROTO_IP`	constant	Dummy protocol for TCP.
`IPPROTO_IPIP`	constant	IPIP tunnels (older KA9Q tunnels use 94).
`IPPROTO_IPV6`	constant	IPv6 header.
`IPPROTO_MAX`	constant	Maximum value for IPPROTO options.
`IPPROTO_MTP`	constant	Multicast Transport Protocol.
`IPPROTO_NONE`	constant	IPv6 no next header.
`IPPROTO_PIM`	constant	Protocol Independent Multicast.
`IPPROTO_PUP`	constant	PUP protocol.
`IPPROTO_RAW`	constant	Raw IP packets.
`IPPROTO_ROUTING`	constant	IPv6 routing header.
`IPPROTO_RSVP`	constant	Reservation Protocol.
`IPPROTO_SCTP`	constant	Stream Control Transmission Protocol.
`IPPROTO_TCP`	constant	Transmission Control Protocol.
`IPPROTO_TP`	constant	SO Transport Protocol Class 4.
`IPPROTO_UDP`	constant	User Datagram Protocol.
`IPV6_ADD_MEMBERSHIP`	constant	Undocumented Getsockopt option ?
`IPV6_ADDRFORM`	constant	Change the IPV6 address into a different address family. Deprecated.
`IPV6_AUTHHDR`	constant	GetSockOpt/SetSockopt: Deliver authentication header messages.
`IPV6_CHECKSUM`	constant	Undocumented Getsockopt option ?
`IPV6_DROP_MEMBERSHIP`	constant	Undocumented Getsockopt option ?
`IPV6_DSTOPTS`	constant	Deliver destination option control messages.
`IPV6_HOPLIMIT`	constant	Deliver an integer containing the HOP count.
`IPV6_HOPOPTS`	constant	Deliver hop option control messages.
`IPV6_IPSEC_POLICY`	constant	Undocumented Getsockopt option ?
`IPV6_JOIN_ANYCAST`	constant	Undocumented Getsockopt option ?
`IPV6_JOIN_GROUP`	constant	GetSockOpt/SetSockopt: Control membership (join group) in multicast groups.
`IPV6_LEAVE_ANYCAST`	constant	Undocumented Getsockopt option ?
`IPV6_LEAVE_GROUP`	constant	GetSockOpt/SetSockopt: Control membership (leave group)in multicast groups.
`IPV6_MTU`	constant	GetSockOpt/SetSockopt: Get/Set the MTU for the socket.
`IPV6_MTU_DISCOVER`	constant	GetSockOpt/SetSockopt: Get/Set Control path MTU Discovery on the socket.
`IPV6_MULTICAST_HOPS`	constant	GetSockOpt/SetSockopt: Get/Set the multicast hop limit.
`IPV6_MULTICAST_IF`	constant	GetSockOpt/SetSockopt: Get/Set device for multicast packages on the socket.
`IPV6_MULTICAST_LOOP`	constant	GetSockOpt/SetSockopt: Control whether socket sees multicast packages that it has sent itself.
`IPV6_NEXTHOP`	constant	sendmsg: set next hop for IPV6 datagram.
`IPV6_PKTINFO`	constant	Change delivery options for incoming IPV6 datagrams.
`IPV6_PKTOPTIONS`	constant	Undocumented Getsockopt option ?
`IPV6_PMTUDISC_DO`	constant	Always DF.
`IPV6_PMTUDISC_DONT`	constant	Never send DF frames.
`IPV6_PMTUDISC_WANT`	constant	Use per route hints.
`IPV6_RECVERR`	constant	GetSockOpt/SetSockopt: Control receiving of asynchronous error options.
`IPV6_ROUTER_ALERT`	constant	GetSockOpt/SetSockopt: Get/Set Pass all forwarded packets containing router alert option.
`IPV6_RTHDR`	constant	Deliver routing header control messages.
`IPV6_RTHDR_LOOSE`	constant	Hop doesn't need to be neighbour.
`IPV6_RTHDR_STRICT`	constant	Hop must be a neighbour.
`IPV6_RTHDR_TYPE_0`	constant	IPv6 Routing header type 0.
`IPV6_RXDSTOPTS`	constant	Undocumented Getsockopt option ?
`IPV6_RXHOPOPTS`	constant	Undocumented Getsockopt option ?
`IPV6_RXSRCRT`	constant	Undocumented Getsockopt option ?
`IPV6_UNICAST_HOPS`	constant	GetSockOpt/SetSockopt: Get/Set unicast hop limit.
`IPV6_V6ONLY`	constant	GetSockOpt/SetSockopt: Handle IPV6 connections only.
`IPV6_XFRM_POLICY`	constant	Undocumented Getsockopt option ?
`IPX_TYPE`	constant	IPX type.
`MCAST_BLOCK_SOURCE`	constant	block from given group.
`MCAST_EXCLUDE`	constant	Undocumented ?
`MCAST_INCLUDE`	constant	Undocumented ?
`MCAST_JOIN_GROUP`	constant	join any-source group.
`MCAST_JOIN_SOURCE_GROUP`	constant	join source-spec group.
`MCAST_LEAVE_GROUP`	constant	leave any-source group.
`MCAST_LEAVE_SOURCE_GROUP`	constant	leave source-spec group.
`MCAST_MSFILTER`	constant	Undocumented ?
`MCAST_UNBLOCK_SOURCE`	constant	unblock from given group.
`MSG_BATCH`	constant	sendmmsg: more messages coming.
`MSG_CMSG_CLOEXEC`	constant	Set close_on_exec for file descriptor received through SCM_RIGHTS.
`MSG_CMSG_COMPAT`	constant	This message needs 32 bit fixups.
`MSG_CONFIRM`	constant	Send flags: Conform connection.
`MSG_CTRUNC`	constant	Receive flags: Control Data was discarded (buffer too small).
`MSG_DONTROUTE`	constant	Send flags: don't use gateway.
`MSG_DONTWAIT`	constant	Receive flags: Non-blocking operation request.
`MSG_EOF`	constant	Alias for MSG_FIN.
`MSG_EOR`	constant	Receive flags: End of record.
`MSG_ERRQUERE`	constant	Receive flags: ?
`MSG_FASTOPEN`	constant	Send data in TCP SYN.
`MSG_FIN`	constant	Receive flags: ?
`MSG_MORE`	constant	Receive flags: ?
`MSG_NO_SHARED_FRAGS`	constant	sendpage internal : page frags are not shared.
`MSG_NOSIGNAL`	constant	Receive flags: Suppress SIG_PIPE signal.
`MSG_OOB`	constant	Receive flags: receive out-of-band data.
`MSG_PEEK`	constant	Receive flags: peek at data, don't remove from buffer.
`MSG_PROBE`	constant	Do not send. Only probe path f.e. for MTU.
`MSG_PROXY`	constant	Receive flags: ?
`MSG_RST`	constant	Receive flags: ?
`MSG_SENDPAGE_DECRYPTED`	constant	sendpage() internal : page may carry plain text and require encryption.
`MSG_SENDPAGE_NOPOLICY`	constant	sendpage internal : do not apply policy.
`MSG_SENDPAGE_NOTLAST`	constant	sendpage internal : not the last page.
`MSG_SYN`	constant	Receive flags: ?
`MSG_TRUNC`	constant	Receive flags: packet Data was discarded (buffer too small).
`MSG_TRYHARD`	constant	Receive flags: ?
`MSG_WAITALL`	constant	Receive flags: Wait till operation completed.
`MSG_WAITFORONE`	constant	recvmmsg(): block until 1+ packets avail.
`MSG_ZEROCOPY`	constant	Use user data in kernel path.
`NoAddress`	constant	Constant indicating invalid (no) network address.
`NoAddress6`	constant	Constant indicating invalid (no) IPV6 network address.
`NoNet`	constant	Constant indicating invalid (no) network address.
`NoNet6`	constant	Constant indicating invalid (no) IPV6 network address.
`PF_ALG`	constant	Protocol family: Algorithm sockets.
`PF_APPLETALK`	constant	Protocol family: Appletalk DDP.
`PF_ASH`	constant	Protocol family: Ash.
`PF_ATMPVC`	constant	Protocol family: ATM PVCs.
`PF_ATMSVC`	constant	Protocol family: ATM SVCs.
`PF_AX25`	constant	Protocol family: Amateur Radio AX.25.
`PF_BLUETOOTH`	constant	Protocol family: Bluetooth sockets.
`PF_BRIDGE`	constant	Protocol family: Multiprotocol bridge.
`PF_CAIF`	constant	Protocol family: CAIF (Application CPU interface) sockets.
`PF_CAN`	constant	Protocol family: CAN (Controller Area Network) sockets.
`PF_DECnet`	constant	Protocol Family: DECNET project.
`PF_ECONET`	constant	Protocol family: Acorn Econet.
`PF_IB`	constant	Protocol family: IB (InfiniBand) sockets.
`PF_IEEE802154`	constant	Protocol family: IEEE802154 sockets.
`PF_INET`	constant	Protocol family: Internet IP Protocol.
`PF_INET6`	constant	Protocol family: IP version 6.
`PF_IPX`	constant	Protocol family: Novell IPX.
`PF_IRDA`	constant	Protocol family: IRDA sockets.
`PF_ISDN`	constant	Protocol Family: ?
`PF_IUCV`	constant	Protocol family: IUCV (Inter User Communication Vehicle) sockets.
`PF_KCM`	constant	Protocol family: KCM (Kernel Connection Multiplexor) sockets.
`PF_KEY`	constant	Protocol family: Key management API.
`PF_LLC`	constant	Protocol family: Linux LLC.
`PF_LOCAL`	constant	Protocol family: Unix socket.
`PF_MAX`	constant	Protocol family: Maximum value.
`PF_MPLS`	constant	Protocol family: MPLS (Multiprotocol Label Switching.
`PF_NETBEUI`	constant	Protocol family: Reserved for 802.2LLC project.
`PF_NETLINK`	constant	Protocol family: ?
`PF_NETROM`	constant	Protocol family:Amateur radio NetROM.
`PF_NFC`	constant	Protocol family: NFC (Near Field Communication) sockets.
`PF_PACKET`	constant	Protocol family: Packet family.
`PF_PHONET`	constant	Protocol family: RxRPC sockets.
`PF_PPPOX`	constant	Protocol family: PPPoX sockets.
`PF_QIPCRTR`	constant	Protocol family: IPCRTR (Qualcomm IPC Router) sockets.
`PF_RDS`	constant	Protocol family: RDS (Reliable Datagram Sockets) sockets.
`PF_ROSE`	constant	Protocol family: Amateur Radio X.25 PLP.
`PF_ROUTE`	constant	Protocol Family: ?
`PF_RXRPC`	constant	Protocol family: RxRPC sockets.
`PF_SECURITY`	constant	Protocol family: Security callback pseudo PF.
`PF_SMC`	constant	Protocol family: SMC (Shared Memory Communication) sockets.
`PF_SNA`	constant	Protocol Family: Linux SNA project.
`PF_TIPC`	constant	Protocol family: TIPC sockets.
`PF_UNIX`	constant	Protocol family: Unix domain sockets.
`PF_UNSPEC`	constant	Protocol family: Unspecified.
`PF_VSOCK`	constant	Protocol family: VSOCK (hypervisor) sockets.
`PF_WANPIPE`	constant	Protocol family: Wanpipe API Sockets.
`PF_X25`	constant	Protocol family: Reserved for X.25 project.
`PF_XDP`	constant	Protocol family: XDP (Express Data Path) sockets.
`S_IN`	constant	Input socket in socket pair.
`S_OUT`	constant	Output socket in socket pair.
`SCM_CREDENTIALS`	constant	socket control messages : credentials.
`SCM_RIGHTS`	constant	socket control messages : access rights.
`SCM_SECURITY`	constant	socket control messages : security label.
`SCM_SRCRT`	constant	Undocumented Getsockopt option ?
`SCM_TIMESTAMP`	constant	Socket option: ?
`SHUT_RD`	constant	Shutdown read part of full duplex socket.
`SHUT_RDWR`	constant	Shutdown read and write part of full duplex socket.
`SHUT_WR`	constant	Shutdown write part of full duplex socket.
`SO_ACCEPTCONN`	constant	Socket option: ?
`SO_ATTACH_FILTER`	constant	Socket option: ?
`SO_BINDTODEVICE`	constant	Socket option: ?
`SO_BROADCAST`	constant	Socket option: Broadcast.
`SO_BSDCOMPAT`	constant	Socket option: ?
`SO_DEBUG`	constant	Socket option level: debug.
`SO_DETACH_FILTER`	constant	Socket option: ?
`SO_DONTROUTE`	constant	Socket option: Don't route.
`SO_ERROR`	constant	Socket option: Error.
`SO_KEEPALIVE`	constant	Socket option: keep alive.
`SO_LINGER`	constant	Socket option: ?
`SO_NO_CHECK`	constant	Socket option: ?
`SO_OOBINLINE`	constant	Socket option: ?
`SO_PASSCRED`	constant	Socket option: ?
`SO_PEERCRED`	constant	Socket option: ?
`SO_PEERNAME`	constant	Socket option: ?
`SO_PRIORITY`	constant	Socket option: ?
`SO_RCVBUF`	constant	Socket option: receive buffer.
`SO_RCVLOWAT`	constant	Socket option: ?
`SO_RCVTIMEO`	constant	Socket option: ?
`SO_REUSEADDR`	constant	Socket option: Reuse address.
`SO_REUSEPORT`	constant	Socket Option : reuse port.
`SO_SECURITY_AUTHENTICATION`	constant	Socket option: ?
`SO_SECURITY_ENCRYPTION_NETWORK`	constant	Socket option: ?
`SO_SECURITY_ENCRYPTION_TRANSPORT`	constant	Socket option: ?
`SO_SNDBUF`	constant	Socket option: Send buffer.
`SO_SNDLOWAT`	constant	Socket option: ?
`SO_SNDTIMEO`	constant	Socket option: ?
`SO_TIMESTAMP`	constant	Socket option: ?
`SO_TYPE`	constant	Socket option: Type.
`SOCK_DGRAM`	constant	Type of socket: datagram (conn.less) socket (UDP).
`SOCK_MAXADDRLEN`	constant	Maximum socket address length for call.
`SOCK_RAW`	constant	Type of socket: raw socket.
`SOCK_RDM`	constant	Type of socket: reliably-delivered message.
`SOCK_SEQPACKET`	constant	Type of socket: sequential packet socket.
`SOCK_STREAM`	constant	Type of socket: stream (connection) type socket (TCP).
`SOL_AAL`	constant	Socket level: AAL.
`SOL_ALG`	constant	Socket level: Algorithm socket.
`SOL_ATALK`	constant	Socket level: Apple talk.
`SOL_ATM`	constant	Socket level: ATM.
`SOL_AX25`	constant	Socket level: AX25.
`SOL_BLUETOOTH`	constant	Socket level: BlueTooth.
`SOL_CAIF`	constant	Socket level: CAIF (Application CPU interface).
`SOL_DCCP`	constant	Socket level: DCCP.
`SOL_DECNET`	constant	Socket level: DECnet.
`SOL_ICMPV6`	constant	Socket level values for IPv6: ICMPV6.
`SOL_IP`	constant	Undocumented ?
`SOL_IPV6`	constant	Socket level values for IPv6: IPV6.
`SOL_IPX`	constant	Socket level: IPX.
`SOL_IRDA`	constant	Socket level: IRDA.
`SOL_IUCV`	constant	Socket level: IUCV (Inter User Communication Vehicle).
`SOL_KCM`	constant	Socket level: KCM (Kernel Connection Multiplexor) sockets.
`SOL_LLC`	constant	Socket level: LLC.
`SOL_NETBEUI`	constant	Socket level: NETBEUI.
`SOL_NETLINK`	constant	Socket level: NETLink.
`SOL_NETROM`	constant	Socket level: Net ROM.
`SOL_NFC`	constant	Socket level: NFC (Near Field Communication) socket.
`SOL_PACKET`	constant	Socket level: Packet.
`SOL_PNPIPE`	constant	Socket level: PNPIPE.
`SOL_PPPOL2TP`	constant	Socket level: PPPOL2TP.
`SOL_RAW`	constant	Socket level: raw socket.
`SOL_RDS`	constant	Socket level: RDS (Reliable Datagram Socket).
`SOL_ROSE`	constant	Socket level: ROSE.
`SOL_RXRPC`	constant	Socket level: RxRPC.
`SOL_SCTP`	constant	Socket level: SCTP.
`SOL_SOCKET`	constant	Socket option level: Socket level.
`SOL_TCP`	constant	Socket level: TCP.
`SOL_TIPC`	constant	Socket level: TIPC.
`SOL_TLS`	constant	Socket level: TLS.
`SOL_UDP`	constant	Socket level: UDP.
`SOL_UDPLITE`	constant	Socket level: UDP Lite.
`SOL_X25`	constant	Socket level: X25.
`SOL_XDP`	constant	Socket level: XDP (Express Data Path) sockets.
`SOMAXCONN`	constant	Maximum queue length specifiable by listen.
`TCP_CONGESTION`	constant	Get/set the congestion-control algorithm for this socket.
`TCP_CORK`	constant	Get/Set CORK algorithm: Send only complete packets.
`TCP_DEFER_ACCEPT`	constant	Get/Set deferred accept on server socket.
`TCP_INFO`	constant	Get TCP connection information (Linux only).
`TCP_KEEPCNT`	constant	Get/Set retry count for unacknowledged KEEPALIVE transmissions.
`TCP_KEEPIDLE`	constant	Get/Set inactivity interval between KEEPALIVE transmissions.
`TCP_KEEPINTVL`	constant	Get/Set retry interval for unacknowledged KEEPALIVE transmissions.
`TCP_LINGER2`	constant	Get/Set Linger2 flag.
`TCP_MAXSEG`	constant	Get/Set Maximum segment size.
`TCP_MD5SIG`	constant	Get/Set TCP MD5 signature option.
`TCP_NODELAY`	constant	Get/Set No delay flag: disable Nagle algorithm.
`TCP_QUICKACK`	constant	Get/Set quick ACK packet option.
`TCP_SYNCNT`	constant	Get/Set number of SYN packets to send before giving up on connection establishment.
`TCP_WINDOW_CLAMP`	constant	Get/Set maximum packet size.
`UDP_CORK`	constant	Get/Set UDP CORK algorithm on datagram sockets.
`UDP_ENCAP`	constant	Get/Set UDP encapsulation flag for IPSec datagram sockets.
`UDP_ENCAP_ESPINUDP`	constant	? Undocumented datagram option, IPSec related.
`UDP_ENCAP_ESPINUDP_NON_IKE`	constant	? Undocumented datagram option, IPSec related.
`UDP_ENCAP_L2TPINUDP`	constant	? Undocumented datagram option, IPSec related.

Uses

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.