| INT WINAPI InetGetHostName(
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LPINTERNET_ADDRESS lpAddress, |
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LPTSTR lpszHostName, |
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INT cchHostName |
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The InetGetHostName function performs a reverse lookup,
returning the host name associated with a given IP address.
Parameters
- lpAddress
- A pointer to an INTERNET_ADDRESS structure which
specifies the IP address that should be resolved into a host
name.
- lpszHostName
- A pointer to the buffer that will contain the host name. It is
recommended that this buffer be at least 256 characters in length
to accommodate the longest possible fully qualified domain
name.
- cchHostName
- The maximum number of characters that can be copied into the
buffer.
Return Value
If the function succeeds, the return value is the length of the
hostname. If the function fails, the return value is INET_ERROR. To
get extended error information, call InetGetLastError.
Remarks
If the function must perform a reverse DNS lookup to resolve the
IP address into a host name, the calling thread will block. This
function requires that the host have a PTR record, otherwise it
will fail. Because many hosts do not have a PTR record, calling
this function frequently may have a negative impact on the overall
performance of the application.
To determine if the local system has an IPv6 TCP/IP stack
installed and configured on the local system, use the
InetIsProtocolAvailable function. If an IPv6 stack is not
installed, this function will fail if the lpAddress
parameter specifies an IPv6 address, even if the address itself is
valid.
Requirements
Client: Requires Windows 7, Windows Vista or Windows
XP.
Server: Requires Windows Server 2008 or Windows Server
2003.
Header: Include cswsock7.h.
Library: Use cswskav7.lib.
Unicode: Implemented as Unicode and ANSI versions.
See Also
InetGetHostAddress,
InetGetLocalAddress,
InetGetLocalName, InetGetPeerAddress, InetIsProtocolAvailable,
INTERNET_ADDRESS
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