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gethostname function

The gethostname function retrieves the standard host name for the local computer.

Syntax


int gethostname(
  _Out_  char *name,
  _In_   int namelen
);

Parameters

name [out]

A pointer to a buffer that receives the local host name.

namelen [in]

The length, in bytes, of the buffer pointed to by the name parameter.

Return value

If no error occurs, gethostname returns zero. Otherwise, it returns SOCKET_ERROR and a specific error code can be retrieved by calling WSAGetLastError.

Error codeMeaning
WSAEFAULT

The name parameter is a NULL pointer or is not a valid part of the user address space. This error is also returned if the buffer size specified by namelen parameter is too small to hold the complete host name.

WSANOTINITIALISED

A successful WSAStartup call must occur before using this function.

WSAENETDOWN

The network subsystem has failed.

WSAEINPROGRESS

A blocking Windows Sockets 1.1 call is in progress, or the service provider is still processing a callback function.

 

Remarks

The gethostname function returns the name of the local host into the buffer specified by the name parameter. The host name is returned as a null-terminated string. The form of the host name is dependent on the Windows Sockets provider—it can be a simple host name, or it can be a fully qualified domain name. However, it is guaranteed that the name returned will be successfully parsed by gethostbyname and WSAAsyncGetHostByName.

The maximum length of the name returned in the buffer pointed to by the name parameter is dependent on the namespace provider.

If the gethostname function is used on a cluster resource on Windows Server 2008, Windows Server 2003, or Windows 2000 Server and the _CLUSTER_NETWORK_NAME_ environment variable is defined, then the value in this environment variable overrides the actual hostname and is returned. On a cluster resource, the _CLUSTER_NETWORK_NAME_ environment variable contains the name of the cluster.

The gethostname function queries namespace providers to determine the local host name using the SVCID_HOSTNAME GUID defined in the Svgguid.h header file. If no namespace provider responds, then the gethostname function returns the NetBIOS name of the local computer.

The maximum length, in bytes, of the string returned in the buffer pointed to by the name parameter is dependent on the namespace provider, but this string must be 256 bytes or less. So if a buffer of 256 bytes is passed in the name parameter and the namelen parameter is set to 256, the buffer size will always be adequate.

Note  If no local host name has been configured, gethostname must succeed and return a token host name that gethostbyname or WSAAsyncGetHostByName can resolve.

Windows Phone 8: This API is supported.

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Winsock2.h

Library

Ws2_32.lib

DLL

Ws2_32.dll

See also

Winsock Reference
Winsock Functions
gethostbyname
WSAAsyncGetHostByName

 

 

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