GetComputerName Function

Retrieves the NetBIOS name of the local computer. This name is established at system startup, when the system reads it from the registry.

GetComputerName retrieves only the NetBIOS name of the local computer. To retrieve the DNS host name, DNS domain name, or the fully qualified DNS name, call the GetComputerNameEx function. Additional information is provided by the IADsADSystemInfo interface.

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.

Syntax

C++ 
BOOL WINAPI GetComputerName(
  __out    LPTSTR lpBuffer,
  __inout  LPDWORD lpnSize
);

Parameters

lpBuffer [out]

A pointer to a buffer that receives the computer name or the cluster virtual server name. The buffer size should be large enough to contain MAX_COMPUTERNAME_LENGTH + 1 characters.

lpnSize [in, out]

On input, specifies the size of the buffer, in TCHARs. On output, 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_BUFFER_OVERFLOW. The lpnSize parameter specifies the size of the buffer required, including the terminating null character.

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.

Remarks

The GetComputerName function retrieves the NetBIOS name established at system startup. Name changes made by the SetComputerName or SetComputerNameEx functions do not take effect until the user restarts the computer.

If the caller is running under a client session, this function returns the server name. To retrieve the client name, use the WTSQuerySessionInformation function.

Examples

For an example, see Getting System Information.

Requirements

Minimum supported clientWindows 2000 Professional
Minimum supported serverWindows 2000 Server
HeaderWinbase.h (include Windows.h)
LibraryKernel32.lib
DLLKernel32.dll
Unicode and ANSI namesGetComputerNameW (Unicode) and GetComputerNameA (ANSI)

See Also

Computer Names
GetComputerNameEx
SetComputerName
SetComputerNameEx
System Information Functions

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Build date: 11/19/2009

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Community Content

Stanley Roark
The ANSI version does not return the required length
I have to maintain an old application that uses ANSI.
I have noticed that, while the Unicode version returns the required buffer length, the ANSI version does not.
So, on my Windows XP SP2 machine, this code prints 8:
DWORD computerNameLength = 0;
GetComputerNameW(0, &computerNameLength);
cout << computerNameLength << endl;
But if I change it to use GetComputerNameA, it prints 0.
Did anybody else notice this?

Stanley Roark
The ANSI version does not return the required length
I am also noticing something similar. GetComputerNameA does not return the required length, if the input length (second param) is 0 or less than the required length, the output length(second param) is just the same as input length. Also if GetComputerNameW is used in the following way:

DWORD dwCompNameLen = 0;
GetComputerNameW(0, &dwCompNameLen);

the value of dwCompNameLen includes the terminating NULL character too, which is not expected.

Tags : contentbug?

Ruben Alvarado
vb.net syntax
<DllImport("kernel32.dll", CharSet:=CharSet.Auto)> _
Public Shared Function GetComputerName(ByVal nameBuffer As StringBuilder, ByRef bufferSize As Integer) As Integer
End Function
Tags : vb.net syntax

dmex
C# syntax
[DllImport("kernel32.dll", CharSet=CharSet.Auto)]
internal static extern int GetComputerName(StringBuilder nameBuffer, ref int bufferSize);
Tags : c# syntax

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