Winsock Structures

The following list provides concise descriptions of each Winsock structure and typedef. For additional information on any structure or typedef, click the structure or typedef name.

Structure	Description
addrinfo	Used by the getaddrinfo function to hold host address information.
addrinfoW	Used by the GetAddrInfoW function to hold host address information.
ADDRINFO_DNS_SERVER	Represents a custom Domain Name System (DNS) server, used in the Winsock APIs.
addrinfoex	Used by the GetAddrInfoEx function to hold host address information.
addrinfoex2	Used by the GetAddrInfoEx function to hold host address information when both a canonical name and a fully qualified domain name have been requested.
addrinfoex3	Used by the GetAddrInfoEx function to hold host address information when a specific network interface has been requested.
addrinfoex4	Used by the GetAddrInfoEx function to hold host address information when a handle to the fully qualified domain name has been requested.
addrinfoex5	Used by the GetAddrInfoEx function to hold host address information when a handle to the fully qualified domain name has been requested.
addrinfoex6	Used by the GetAddrInfoEx function to hold host address information when a handle to the fully qualified domain name has been requested.
AFPROTOCOLS	Supplies a list of protocols to which application programmers can constrain queries. Used for query purposes only.
BLOB	Contains information about a block of data. Derived from Binary Large Object.
CSADDR_INFO	Contains Winsock address information for a network service or namespace provider.
fd_set	Used by various Winsock functions and service providers, such as select, to place sockets into a "set" for various purposes, such as testing a given socket for readability.
GROUP_FILTER	Provides multicast filtering parameters for multicast IPv6 or IPv4 addresses.
GROUP_REQ	Provides multicast group information for IPv6 or IPv4 addresses.
GROUP_SOURCE_REQ	Provides multicast group information for IPv6 or IPv4 addresses that includes the source IP address.
hostent	Stores information about a given host, such as host name, IP address, and so forth.
in_addr	Represents an IPv4 Internet address.
in_pktinfo	Stores received packet address information, and is used by Windows to return information about received packets.
in6_addr	Represents an IPv6 Internet address.
in6_pktinfo	Stores received IPv6 packet address information, and is used by Windows to return information about received packets.
INET_PORT_RANGE	Provides input data used by the SIO_ACQUIRE_PORT_RESERVATION Ioctl to acquire a runtime reservation for a block of TCP or UDP ports.
INET_PORT_RESERVATION_INSTANCE	Contains a port reservation and a token for a block of TCP or UDP ports.
INET_PORT_RESERVATION_TOKEN	Contains a port reservation token for a block of TCP or UDP ports.
ip_mreq	Provides multicast group information for IPv4 addresses.
ip_mreq_source	Provides multicast group and source information for IPv4 addresses.
ip_msfilter	Provides multicast filtering parameters for IPv4 addresses.
ipv6_mreq	Provides multicast group information for IPv6 addresses.
linger	Maintains information about a specific socket that specifies how that socket should behave when data is queued to be sent and the closesocket function is called on the socket.
NAPI_DOMAIN_DESCRIPTION_BLOB	Describes a domain handled by a namespace provider for the NS_EMAIL namespace.
NAPI_PROVIDER_INSTALLATION_BLOB	Contains the information required to install a namespace provider for the NS_EMAIL namespace.
NS_SERVICE_INFO	Contains information about a network service or a network service type in the context of a specified namespace, or a set of default namespaces.
PROTOCOL_INFO	Contains information about a protocol.
protoent	Contains the name and protocol numbers that correspond to a given protocol name.
REAL_TIME_NOTIFICATION_SETTING_INPUT	Contains input settings to apply for the REAL_TIME_NOTIFICATION_CAPABILITY transport setting for a TCP socket that is used with ControlChannelTrigger to receive background network notifications in a Windows Store app
REAL_TIME_NOTIFICATION_SETTING_OUTPUT	Contains the output settings from a query for the REAL_TIME_NOTIFICATION_CAPABILITY transport setting for a TCP socket that is used with ControlChannelTrigger to receive background network notifications in a Windows Store app.
RIO_EXTENSION_FUNCTION_TABLE	Contains information on the functions that implement the Winsock registered I/O extensions.
RIO_BUF	Specifies a portion of a registered buffer used for sending or receiving network data with the Winsock registered I/O extensions.
RIO_BUFFERID	Specifies a registered buffer descriptor used with the Winsock registered I/O extensions.
RIO_CQ	Specifies a completion queue descriptor used for I/O completion notification by send and receive requests with the Winsock registered I/O extensions.
RIO_NOTIFICATION_COMPLETION	Specifies the method for I/O completion to be used with a RIONotify function for sending or receiving network data with the Winsock registered I/O extensions.
RIO_RQ	Specifies a socket descriptor used by send and receive requests with the Winsock registered I/O extensions.
RIORESULT	Contains data used to indicate request completion results used with the Winsock registered I/O extensions.
RM_FEC_INFO	Specifies settings for using forward error correction (FEC) with Reliable Multicast.
RM_RECEIVER_STATS	Provides statistical information for a Reliable Multicast receiver session.
RM_SEND_WINDOW	Specifies the Reliable Multicast send window.
RM_SENDER_STATS	Provides statistical information for a Reliable Multicast sender session.
servent	Stores or returns the name and service number for a given service name.
SERVICE_ADDRESS	Contains address information for a service.
SERVICE_ADDRESSES	Contains an array of SERVICE_ADDRESS data structures.
SERVICE_INFO	Contains information about a network service or a network service type.
SERVICE_TYPE_INFO_ABS	Contains information about a network service type.
SERVICE_TYPE_VALUE_ABS	Contains information about a network-service type value. The information may be specific to a namespace.
sockaddr	Contains socket address information. The sockaddr structure varies depending on the protocol selected. Limited to IPv4; use SOCKADDR_STORAGE instead.
SOCKADDR_IRDA	Used with IrDA socket operations, defined by address family AF_IRDA.
SOCKADDR_STORAGE	Stores socket address information, and is sufficiently large to store IPv4 or IPv6 address information, promoting protocol-family and protocol-version independence. Use this structure in place of the sockaddr structure.
SOCKET_ADDRESS	Stores protocol-specific address information.
SOCKET_ADDRESS_LIST	Stores an array of SOCKET_ADDRESS structures that contain protocol-specific address information.
SOCKET_PEER_TARGET_NAME	Contains the IP address and name for a peer target and the type of security protocol to be used on a socket.
SOCKET_SECURITY_QUERY_INFO	Contains security information returned by the WSAQuerySocketSecurity function.
SOCKET_SECURITY_QUERY_TEMPLATE	Contains the security template used by the WSAQuerySocketSecurity function.
SOCKET_SECURITY_SETTINGS	Specifies generic security requirements for a socket.
SOCKET_SECURITY_SETTINGS_IPSEC	Specifies various security requirements and settings that are specific to IPsec.
timeval	Used to specify time values. Associated with the Berkeley Software Distribution (BSD) file Time.h.
TRANSMIT_FILE_BUFFERS	Specifies data to be transmitted before and after file data during a TransmitFile transfer operation.
TRANSMIT_PACKETS_ELEMENT	Specifies a single data element to be transmitted by the TransmitPackets function.
TRANSPORT_SETTING_ID	Specifies the transport setting ID used by the SIO_APPLY_TRANSPORT_SETTING and SIO_QUERY_TRANSPORT_SETTING IOCTLs to apply or query the transport setting for a socket.
WSABUF	Enables the creation or manipulation of a data buffer.
WSACOMPLETION	Specifies completion notification settings for I/O control calls made to a registered namespace.
WSADATA	Contains information about the Windows Sockets implementation.
WSAMSG	Stores address and optional control information about connected and unconnected sockets. Used with the LPFN_WSARECVMSG (WSARecvMsg) function.
WSANAMESPACE_INFO	Contains registration information for a namespace provider.
WSANAMESPACE_INFOEX	Contains enhanced registration information for a namespace provider.
WSANETWORKEVENTS	Stores a socket's internal information about network events.
WSANSCLASSINFO	Provides individual parameter information for a specific Winsock namespace.
WSAOVERLAPPED	Provides a communication medium between the initiation of an overlapped I/O operation and its subsequent completion.
WSAPOLLFD	Stores socket information used by the WSAPoll function.
WSAPROTOCOL_INFO	Stores or retrieves complete information for a given protocol.
WSAPROTOCOL_INFOW	Store or retrieves complete information for a given protocol. The protocol name is represented as an array of Unicode characters.
WSAPROTOCOLCHAIN	Contains a counted list of Catalog Entry identifiers that comprise a protocol chain.
WSAQUERYSET	Provides relevant information about a given service.
WSAQUERYSET2	Provides relevant information about a given service.
WSASERVICECLASSINFO	Contains information about a specified service class.
WSAVERSION	Provides version comparison in Winsock.