Retrieves a NetBIOS or DNS name associated with the local computer. The names are established at system startup, when the system reads them from the registry.

Syntax

BOOL WINAPI GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
  __out    LPTSTR lpBuffer,
  __inout  LPDWORD lpnSize
);

Parameters

NameType [in]

The type of name to be retrieved. This parameter is a value from the COMPUTER_NAME_FORMAT enumeration type. The following table provides additional information.

Value	Meaning
ComputerNameDnsDomain	The name of the DNS domain assigned to the local computer. If the local computer is a node in a cluster, lpBuffer receives the DNS domain name of the cluster virtual server.
ComputerNameDnsFullyQualified	The fully qualified DNS name that uniquely identifies the local computer. This name is a combination of the DNS host name and the DNS domain name, using the form HostName.DomainName. If the local computer is a node in a cluster, lpBuffer receives the fully qualified DNS name of the cluster virtual server.
ComputerNameDnsHostname	The DNS host name of the local computer. If the local computer is a node in a cluster, lpBuffer receives the DNS host name of the cluster virtual server.
ComputerNameNetBIOS	The NetBIOS name of the local computer. If the local computer is a node in a cluster, lpBuffer receives the NetBIOS name of the cluster virtual server.
ComputerNamePhysicalDnsDomain	The name of the DNS domain assigned to the local computer. If the local computer is a node in a cluster, lpBuffer receives the DNS domain name of the local computer, not the name of the cluster virtual server.
ComputerNamePhysicalDnsFullyQualified	The fully qualified DNS name that uniquely identifies the computer. If the local computer is a node in a cluster, lpBuffer receives the fully qualified DNS name of the local computer, not the name of the cluster virtual server. The fully qualified DNS name is a combination of the DNS host name and the DNS domain name, using the form HostName.DomainName.
ComputerNamePhysicalDnsHostname	The DNS host name of the local computer. If the local computer is a node in a cluster, lpBuffer receives the DNS host name of the local computer, not the name of the cluster virtual server.
ComputerNamePhysicalNetBIOS	The NetBIOS name of the local computer. If the local computer is a node in a cluster, lpBuffer receives the NetBIOS name of the local computer, not the name of the cluster virtual server.

 

lpBuffer [out]

A pointer to a buffer that receives the computer name or the cluster virtual server name.

The length of the name may be greater than MAX_COMPUTERNAME_LENGTH characters because DNS allows longer names. To ensure that this buffer is large enough, set this parameter to NULL and use the required buffer size returned in the lpnSize parameter.

lpnSize [in, out]

On input, specifies the size of the buffer, in TCHARs. On output, receives the number of TCHARs copied to the destination buffer, not including the terminating null character.

If the buffer is too small, the function fails and GetLastError returns ERROR_MORE_DATA. This parameter receives the size of the buffer required, including the terminating null character.

If lpBuffer is NULL, this parameter must be zero.

Return Value

If the function succeeds, the return value is a nonzero value.

If the function fails, the return value is zero. To get extended error information, call GetLastError. Possible values include the following.

Remarks

If group policy is not set for the local machine, the GetComputerNameEx function retrieves the NetBIOS or DNS names established at system startup. If group policy is set, the function returns the primary domain name set by group policy. Name changes made by the SetComputerName or SetComputerNameEx functions do not take effect until the user restarts the computer.

If the local computer is not configured to use DNS names, GetComputerNameEx will not return DNS information. To configure the computer to do this, follow the steps outlined in the operating system help and change the primary DNS suffix of the computer, then restart the computer.

The behavior of this function can be affected if the local computer is a node in a cluster. For more information, see ResUtilGetEnvironmentWithNetName and UseNetworkName.

If you are working with environments that use different DNS layouts, where the computer's FQDN does not match the FQDN of its domain, use LsaQueryInformationPolicy instead.

To compile an application that uses this function, define the _WIN32_WINNT macro as 0x0500 or later. For more information, see Using the Windows Headers.

Examples

#define _WIN32_WINNT 0x0500

#include <windows.h>
#include <stdio.h>
#include <tchar.h>

void _tmain(void)
{
    TCHAR buffer[256] = TEXT("");
    TCHAR szDescription[8][32] = {TEXT("NetBIOS"), 
        TEXT("DNS hostname"), 
        TEXT("DNS domain"), 
        TEXT("DNS fully-qualified"), 
        TEXT("Physical NetBIOS"), 
        TEXT("Physical DNS hostname"), 
        TEXT("Physical DNS domain"), 
        TEXT("Physical DNS fully-qualified")};
    int cnf = 0;
    DWORD dwSize = sizeof(buffer);
	
    for (cnf = 0; cnf < ComputerNameMax; cnf++)
    {
        if (!GetComputerNameEx((COMPUTER_NAME_FORMAT)cnf, buffer, &dwSize))
        {
            _tprintf(TEXT("GetComputerNameEx failed (%d)\n"), GetLastError());
            return;
        }
        else _tprintf(TEXT("%s: %s\n"), szDescription[cnf], buffer);

        dwSize = sizeof(buffer);
        ZeroMemory(buffer, dwSize);
    }
}

Requirements

See Also

Computer Names

COMPUTER_NAME_FORMAT

GetComputerName

ResUtilGetEnvironmentWithNetName

ResUtilSetResourceServiceStartParameters

ResUtilSetResourceServiceEnvironment

SetComputerName

SetComputerNameEx

System Information Functions

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Build date: 11/19/2009