WinSock Compatibility Issues

Using WSAStartup and WSACleanup

Unlike their use from Windows, in an RTSS process, WSAStartup and WSACleanup should only be called once within an RT-TCP/IP process.

Unsupported WinSock APIs

The following section describes the details of the most commonly used WinSock APIs that are NOT supported by the WinSock compatibility layer of the protocol stack.

NOTE: This list covers only the most commonly used APIs. When in doubt, refer to the individual API descriptions in this help system for detailed information about what is supported/unsupported for any given API.

API	Unsupported Features
getsockopt	Some values for the optname parameter are not supported. See Unsupported Options for getsockopt and setsockopt below.
recv	The following values for the optname parameter is not supported: MSG_WAITALL
setsockopt	Some values for the optname parameter are not supported. See Unsupported Options for getsockopt and setsockopt below.
getaddrinfo	The following values for the ai_flags in the hints parameter are not supported: AI_ADDRCONFIG AI_NON_AUTHORITATIVE AI_SECURE AI_RETURN_PREFERRED_NAMES
getnameinfo	The following values for the flag parameter are not supported: NI_NOFQDN NI_NAMEREQD NI_DGRAM
ioctlsocket	The following command is not supported under RTX 8.1 and earlier: FIONREAD
WSAEventSelect	The following network event types are not supported in the RT-TCP/IP stack: FD_QOS FD_GROUP_QOS FD_ROUTING_INTERFACE_CHANGE FD_ADDRESS_LIST_CHANGE
getsockopt	Some values for the optname parameter are not supported. See Unsupported Options for getsockopt and setsockopt below.
recv	The following values for the optname parameter is not supported: MSG_WAITALL
setsockopt	Some values for the optname parameter are not supported. See Unsupported Options for getsockopt and setsockopt below.
getaddrinfo	The following values for the ai_flags in the hints parameter are not supported: AI_ADDRCONFIG AI_NON_AUTHORITATIVE AI_SECURE AI_RETURN_PREFERRED_NAMES
getnameinfo	The following values for the flag parameter are not supported: NI_NOFQDN NI_NAMEREQD NI_DGRAM
ioctlsocket	The following command is not supported under RTX 8.1 and earlier: FIONREAD
WSAEventSelect	The following network event types are not supported in the RT-TCP/IP stack: FD_QOS FD_GROUP_QOS FD_ROUTING_INTERFACE_CHANGE FD_ADDRESS_LIST_CHANGE

IP_TOS (Differentiated Services filed) now complies with RFC 2474 under RTX. You can set this option under IPPROTO_IP level with IP_TOS option.

Unsupported Options for getsockopt and setsockopt

Some values for the optname parameter are not supported for the getsockopt and setsockopt functions. The following sections list the unsupported options by socket type.

IMPORTANT! None of the options for the IPPROTO_RM, NSPROTO_IPX, SOL_APPLETALK, and SOL_IRLMP socket types are supported.

Unsupported IPPROTO_IP socket options:

IP_HDRINCL
IP_OPTIONS
IP_PKTINFO
IP_RECEIVE_BROADCAST

Unsupported IPPROTO_IPV6 socket options:

IPV6_ADD_MEMBERSHIP
IPV6_DROP_MEMBERSHIP
IPV6_HDRINCL
IPV6_HOPLIMIT
IPV6_MULTICAST_LOOP
IPV6_PKTINFO
IPV6_PROTECTION_LEVEL
IPV6_UNICAST_HOPS
IPV6_V6ONLY

Unsupported IPPROTO_TCP socket options:

TCP_BSDURGENT
TCP_EXPEDITED_1122

Unsupported IPPROTO_UDP socket options:

UDP_CHECKSUM_COVERAGE
UDP_NOCHECKSUM

Unsupported SOL_SOCKET socket options:

PVD_CONFIG
SO_BSP_STATE
SO_CONDITIONAL_ACCEPT
SO_CONNDATA
SO_CONNDATALEN
SO_CONNECT_TIME
SO_CONNOPT
SO_CONNOPTLEN
SO_DISCDATA
SO_DISCDATALEN
SO_DISCOPT
SO_DISCOPTLEN
SO_DONTLINGER
SO_ERROR
SO_GROUP_ID
SO_GROUP_PRIORITY
SO_MAX_MSG_SIZE
SO_MAXDG
SO_MAXPATHDG
SO_OPENTYPE
SO_PORT_SCALABILITY
SO_PROTOCOL_INFO
SO_PROTOCOL_INFOA
SO_PROTOCOL_INFOW
SO_RCVLOWAT
SO_RCVTIMEO
SO_SNDLOWAT
SO_SNDTIMEO
SO_TYPE
SO_UPDATE_ACCEPT_CONTEXT
SO_UPDATE_CONNECT_CONTEXT
SO_USELOOPBACK

Fragmentation with getsockopt and setsockopt

The IP_DONTFRAGMENT socket option, which is at the IPPROTO_IP level, has a default of 1 (fragmentation disabled) for getsockopt and setsockopt.