The DnsFree function frees memory allocated for DNS records that was obtained using the DnsQuery function.
函數原型定義:Parameters
- pData
A pointer to the DNS data to be freed.
- FreeType
A value that specifies the type of DNS data in pData. For more information and a list of values, see the DNS_FREE_TYPE enumeration.
Return Value
This function does not return a value.Requirements
Client | Requires Windows Vista or Windows XP. |
---|---|
Server | Requires Windows Server 2008 or Windows Server 2003. |
Header |
Declared in Windns.h. |
Library |
Use Dnsapi.lib. |
DLL |
Requires Dnsapi.dll. |
The DnsAcquireContextHandle function type acquires a context handle to a set of credentials. Like many DNS functions, the DnsAcquireContextHandle function type is implemented in multiple forms to facilitate different character encoding. Based on the character encoding involved, use one of the following functions:
DnsAcquireContextHandle_A (_A for ANSI encoding)
DnsAcquireContextHandle_W (_W for Unicode encoding)
If the DnsAcquireContextHandle function type is called without its suffix (_A or _W), a compiler error will occur.
函數原型定義:
Parameters
- CredentialFlags
Flag indicating character encoding. Set to TRUE for Unicode, FALSE for ANSI.
- Credentials
Pointer to the SEC_WINNT_AUTH_IDENTITY_W structure or the SEC_WINNT_AUTH_IDENTITY_A structure containing the name, domain, and password of the account to be used in a secure dynamic update. If not specified, the credentials of the calling service are used. This parameter is optional.
- ContextHandle
Pointer to a handle pointing to the credentials.
Return Value
Returns success confirmation upon successful completion. Otherwise, returns the appropriate DNS-specific error code as defined in Winerror.h.
Requirements
Client | Requires Windows Vista, Windows XP, or Windows 2000 Professional. |
---|---|
Server | Requires Windows Server 2008, Windows Server 2003, or Windows 2000 Server. |
Header | Declared in Windns.h. |
Library | Use Dnsapi.lib. |
DLL | Requires Dnsapi.dll. |
Unicode | Implemented as DnsAcquireContextHandle_W (Unicode) and DnsAcquireContextHandle_A (ANSI). |
The DnsExtractRecordsFromMessage function type extracts resource records from a DNS message, and stores those records in a DNS_RECORD structure. Like many DNS functions, the DnsExtractRecordsFromMessage function type is implemented in multiple forms to facilitate different character encoding. Based on the character encoding involved, use one of the following functions:
DnsExtractRecordsFromMessage_W (_W for Unicode encoding)
DnsExtractRecordsFromMessage_UTF8 (_UTF8 for UTF-8 encoding)
If the DnsExtractRecordsFromMessage function type is called without its suffix (either _W or _UTF8), a compiler error will occur.
函數定義原型:
DNS_STATUS WINAPI DnsExtractRecordsFromMessage( __in PDNS_MESSAGE_BUFFER pDnsBuffer, __in WORD wMessageLength, __inout PDNS_RECORD* ppRecord );
Parameters
- pDnsBuffer
-
Pointer to a DNS response message stored in a DNS_MESSAGE_BUFFER structure.
- wMessageLength
-
Size of the message stored in DNS_MESSAGE_BUFFER, in bytes.
- ppRecord
-
Pointer to a pointer to the list of extracted RRs. To free these records, use the DnsRecordListFree function.
Return Value
Returns success confirmation upon successful completion. Otherwise, returns the appropriate DNS-specific error code as defined in Winerror.h.
Remarks
The DnsExtractRecordsFromMessage function is designed to operate on messages in host byte order. As such, received messages should be converted from network byte order to host byte order before extraction, or before retransmission onto the network. Use the DNS_BYTE_FLIP_HEADER_COUNTS macro to change byte ordering.
Requirements
Client | Requires Windows Vista, Windows XP, or Windows 2000 Professional. |
---|---|
Server | Requires Windows Server 2008, Windows Server 2003, or Windows 2000 Server. |
Header |
Declared in Windns.h. |
Library |
Use Dnsapi.lib. |
DLL |
Requires Dnsapi.dll. |
Unicode |
Implemented as DnsExtractRecordsFromMessage_W (Unicode). |