ADDRINFOEX2A structure (ws2def.h)
The addrinfoex2 structure is used by the GetAddrInfoEx function to hold host address information when both a canonical name and a fully qualified domain name have been requested.
Syntax
typedef struct addrinfoex2A {
int ai_flags;
int ai_family;
int ai_socktype;
int ai_protocol;
size_t ai_addrlen;
char *ai_canonname;
struct sockaddr *ai_addr;
void *ai_blob;
size_t ai_bloblen;
LPGUID ai_provider;
struct addrinfoex2A *ai_next;
int ai_version;
char *ai_fqdn;
} ADDRINFOEX2A, *PADDRINFOEX2A, *LPADDRINFOEX2A;
Members
ai_flags
Flags that indicate options used in the GetAddrInfoEx function.
Supported values for the ai_flags member are defined in the Winsock2.h include file and can be a combination of the following options.
| Value | Meaning |
|---|---|
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The socket address will be used in a call to the bind function. |
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The canonical name is returned in the first ai_canonname member. |
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The nodename parameter passed to the GetAddrInfoEx function must be a numeric string. |
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If this bit is set, a request is made for IPv6 addresses and IPv4 addresses with AI_V4MAPPED.
This option is supported on Windows Vista and later. |
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The GetAddrInfoEx will resolve only if a global address is configured. The IPv6 and IPv4 loopback address is not considered a valid global address.
This option is supported on Windows Vista and later. |
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If the GetAddrInfoEx request for an IPv6 addresses fails, a name service request is made for IPv4 addresses and these addresses are converted to IPv4-mapped IPv6 address format.
This option is supported on Windows Vista and later. |
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The address information is from non-authoritative results.
When this option is set in the pHints parameter of GetAddrInfoEx, the NS_EMAIL namespace provider returns both authoritative and non-authoritative results. If this option is not set, then only authoritative results are returned. This option is only supported on Windows Vista and later for the NS_EMAIL namespace. |
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The address information is from a secure channel.
If the AI_SECURE bit is set, the NS_EMAIL namespace provider will return results that were obtained with enhanced security to minimize possible spoofing. When this option is set in the pHints parameter of GetAddrInfoEx, the NS_EMAIL namespace provider returns only results that were obtained with enhanced security to minimize possible spoofing. This option is only supported on Windows Vista and later for the NS_EMAIL namespace. |
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The address information is for a preferred names for publication with a specific namespace.
When this option is set in the pHints parameter of GetAddrInfoEx, no name should be provided in the pName parameter and the NS_EMAIL namespace provider will return preferred names for publication. This option is only supported on Windows Vista and later for the NS_EMAIL namespace. |
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The fully qualified domain name is returned in the first ai_fqdn member.
When this option is set in the pHints parameter of GetAddrInfoEx and a flat name (single label) is specified in the pName parameter, the fully qualified domain name that the name eventually resolved to will be returned. This option is supported on Windows 7, Windows Server 2008 R2, and later. |
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A hint to the namespace provider that the hostname being queried is being used in a file share scenario. The namespace provider may ignore this hint.
This option is supported on Windows 7, Windows Server 2008 R2, and later. |
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Disable the automatic International Domain Name encoding using Punycode in the name resolution functions called by the GetAddrInfoEx function.
This option is supported on Windows 8, Windows Server 2012, and later. |
ai_family
The address family.
The possible values for the address family are defined in the Ws2def.h header file. Note that the Ws2def.h header file is automatically included in Winsock2.h, and should never be used directly.
The values currently supported are AF_INET or AF_INET6, which are the Internet address family formats for IPv4 and IPv6. Other options for address family (AF_NETBIOS for use with NetBIOS, for example) are supported if a Windows Sockets service provider for the address family is installed. Note that the values for the AF_ address family and PF_ protocol family constants are identical (for example, AF_INET and PF_INET), so either constant can be used.
The table below lists common values for the address family although many other values are possible.
ai_socktype
The socket type. Possible values for the socket type are defined in the Winsock2.h include file.
The following table lists the possible values for the socket type supported for Windows Sockets 2:
| Value | Meaning |
|---|---|
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Provides sequenced, reliable, two-way, connection-based byte streams with an OOB data transmission mechanism. Uses the Transmission Control Protocol (TCP) for the Internet address family (AF_INET or AF_INET6). If the ai_family member is AF_IRDA, then SOCK_STREAM is the only supported socket type. |
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Supports datagrams, which are connectionless, unreliable buffers of a fixed (typically small) maximum length. Uses the User Datagram Protocol (UDP) for the Internet address family (AF_INET or AF_INET6). |
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Provides a raw socket that allows an application to manipulate the next upper-layer protocol header. To manipulate the IPv4 header, the IP_HDRINCL socket option must be set on the socket. To manipulate the IPv6 header, the IPV6_HDRINCL socket option must be set on the socket. |
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Provides a reliable message datagram. An example of this type is the Pragmatic General Multicast (PGM) multicast protocol implementation in Windows, often referred to as reliable multicast programming. |
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Provides a pseudo-stream packet based on datagrams. |
In Windows Sockets 2, new socket types were introduced. An application can dynamically discover the attributes of each available transport protocol through the WSAEnumProtocols function. So an application can determine the possible socket type and protocol options for an address family and use this information when specifying this parameter. Socket type definitions in the Winsock2.h and Ws2def.h header files will be periodically updated as new socket types, address families, and protocols are defined.
In Windows Sockets 1.1, the only possible socket types are SOCK_DATAGRAM and SOCK_STREAM.
ai_protocol
The protocol type. The possible options are specific to the address family and socket type specified. Possible values for the ai_protocol are defined in Winsock2.h and the Wsrm.h header files.
On the Windows SDK released for Windows Vista and later,, the organization of header files has changed and this member can be one of the values from the IPPROTO enumeration type defined in the Ws2def.h header file. Note that the Ws2def.h header file is automatically included in Winsock2.h, and should never be used directly.
If a value of 0 is specified for ai_protocol, the caller does not wish to specify a protocol and the service provider will choose the ai_protocol to use. For protocols other than IPv4 and IPv6, set ai_protocol to zero.
The following table lists common values for the ai_protocol member although many other values are possible.
If the ai_family member is AF_IRDA, then the ai_protocol must be 0.
ai_addrlen
The length, in bytes, of the buffer pointed to by the ai_addr member.
ai_canonname
The canonical name for the host.
ai_addr
A pointer to a sockaddr structure. The ai_addr member in each returned addrinfoex2 structure points to a filled-in socket address structure. The length, in bytes, of each returned addrinfoex2 structure is specified in the ai_addrlen member.
ai_blob
A pointer to data that is used to return provider-specific namespace information that is associated with the name beyond a list of addresses. The length, in bytes, of the buffer pointed to by ai_blob must be specified in the ai_bloblen member.
ai_bloblen
The length, in bytes, of the ai_blob member.
ai_provider
A pointer to the GUID of a specific namespace provider.
ai_next
A pointer to the next structure in a linked list. This parameter is set to NULL in the last addrinfoex2 structure of a linked list.
ai_version
The version number of this structure. The value currently used for this version of the structure is 2.
ai_fqdn
The fully qualified domain name for the host.
Remarks
The addrinfoex2 structure is supported on Windows 8 and Windows Server 2012
The addrinfoex2 structure is used by the GetAddrInfoEx function to hold host address information when both the AI_FQDN and AI_CANONNAME bits are set in the ai_flags member of the optional addrinfoex structure provided in the hints parameter to the GetAddrInfoEx function. The addrinfoex2 structure is an enhanced version of the addrinfoex structure that can return both the canonical name and the fully qualified domain name for the host. The extra structure members are for a version number of the structure and the fully qualified domain name for the host.
The addrinfoex2 structure used with GetAddrInfoEx function is an enhanced version of the addrinfo and addrinfoW structures used with the getaddrinfo and GetAddrInfoW functions. The GetAddrInfoEx function allows specifying the namespace provider to resolve the query. For use with the IPv6 and IPv4 protocol, name resolution can be by the Domain Name System (DNS), a local hosts file, an email provider (the NS_EMAIL namespace), or by other naming mechanisms.
The blob data in tha ai_blob member is used to return additional provider-specific namespace information associated with a name. The format of data in the ai_blob member is specific to a particular namespace provider. Currently, blob data is used by the NS_EMAIL namespace provider to supply additional information.
When UNICODE or _UNICODE is defined, addrinfoex2 is defined to addrinfoex2W, the Unicode version of this structure. The string parameters are defined to the PWSTR data type and the addrinfoex2W structure is used.
When UNICODE or _UNICODE is not defined, addrinfoex2 is defined to addrinfoex2A, the ANSI version of this structure. The string parameters are of the char * data type and the addrinfoex2A structure is used.
Upon a successful call to GetAddrInfoEx, a linked list of addrinfoex2 structures is returned in the ppResult parameter passed to the GetAddrInfoEx function. The list can be processed by following the pointer provided in the ai_next member of each returned addrinfoex2 structure until a NULL pointer is encountered. In each returned addrinfoex2 structure, the ai_family, ai_socktype, and ai_protocol members correspond to respective arguments in a socket or WSASocket function call. Also, the ai_addr member in each returned addrinfoex2 structure points to a filled-in socket address structure, the length of which is specified in its ai_addrlen member.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 8 [desktop apps only] |
| Minimum supported server | Windows Server 2012 [desktop apps only] |
| Header | ws2def.h |