Microsoft KB Archive/154512

= SAMPLE: Winsock.exe Getting HostAddress Using Windows Sockets =

Article ID: 154512

Article Last Modified on 8/5/2004

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APPLIES TO


 * Microsoft Visual Basic 5.0 Professional Edition
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 5.0 Enterprise Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition
 * Microsoft Visual Basic 4.0 Standard Edition
 * Microsoft Visual Basic 4.0 Professional Edition
 * Microsoft Visual Basic 4.0 32-Bit Enterprise Edition

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This article was previously published under Q154512



SUMMARY
This article demonstrates how to get the HostAddress of a machine using Windows Sockets. The TCP/IP network protocol is shipped with all Windows operating systems and is becoming increasingly more important with its Internet compatibility. There is an API set for Windows Sockets that can work with TCP/IP and help to return information such as the HostName or the IP Address of a machine. This is obviously reliant on the presence of the relevant DNS or WINS servers and the TCP/IP protocol being installed. Below is a sample showing how to extract the machine HostAddress.

The following file is available for download from the Microsoft Download Center:

Winsock.exe

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

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MORE INFORMATION
NOTE: This code requires at least version 1.1 of Windows Sockets.

 Start a new project in Visual Basic. Form1 is created by default. Place a CommandButton on the form.  Add the following code to the Form1 code window:

Option Explicit

Private Const WSADescription_Len = 256 Private Const WSASYS_Status_Len = 128 Private Const SOCKET_ERROR As Long = -1

Private Type WSADATA wversion As Integer wHighVersion As Integer szDescription(0 To WSADescription_Len) As Byte szSystemStatus(0 To WSASYS_Status_Len) As Byte iMaxSockets As Integer iMaxUdpDg As Integer lpszVendorInfo As Long End Type

Private Declare Function gethostname Lib "WSOCK32.DLL" (ByVal hostname$, _  ByVal HostLen As Integer) As Long

Private Declare Function WSAGetLastError Lib "WSOCK32.DLL" _ As Long Private Declare Function WSAStartup Lib "WSOCK32.DLL" (ByVal _        wVersionRequired as Integer, lpWSAData As WSADATA) As Long Private Declare Function WSACleanup Lib "WSOCK32.DLL" As Long

Sub Form_Load Call SocketsInitialize End Sub

Private Sub Command1_click Dim hostname$, HostLen& HostLen& = 256 hostname$ = Space$(HostLen&) If gethostname(hostname$, HostLen&) = SOCKET_ERROR Then MsgBox "Windows Sockets error" & Str(WSAGetLastError) Else hostname$ = Trim$(hostname$) hostname$ = Left$(hostname$, Len(hostname$) - 1) MsgBox "Host name = " & hostname$ End If       SocketsCleanup End Sub

Sub SocketsInitialize Const WS_VERSION_REQD As Integer = &H101 Const WS_VERSION_MAJOR = WS_VERSION_REQD \ &H100 And &HFF& Const WS_VERSION_MINOR = WS_VERSION_REQD And &HFF& Const MIN_SOCKETS_REQD = 1 Dim WSAD As WSADATA Dim iReturn As Integer Dim sLowByte As String, sHighByte As String, sMsg As String iReturn = WSAStartup(WS_VERSION_REQD, WSAD) If iReturn <> 0 Then MsgBox "Winsock.dll is not responding." End End If       If lobyte(WSAD.wversion) < WS_VERSION_MAJOR Or (lobyte _          (WSAD.wversion) = WS_VERSION_MAJOR And hibyte(WSAD.wversion) _          < WS_VERSION_MINOR) Then sHighByte = Trim$(Str$(hibyte(WSAD.wversion))) sLowByte = Trim$(Str$(lobyte(WSAD.wversion))) sMsg = "Windows Sockets version " & sLowByte & "." & sHighByte sMsg = sMsg & " is not supported by winsock.dll " MsgBox sMsg: End End If    If WSAD.iMaxSockets < MIN_SOCKETS_REQD Then sMsg = "This application requires a minimum of " sMsg = sMsg & Trim$(Str$(MIN_SOCKETS_REQD)) & _ " supported sockets." MsgBox sMsg End End If     End Sub

Function hibyte(ByVal wParam As Integer) hibyte = wParam \ &H100 And &HFF& End Function

Function lobyte(ByVal wParam As Integer) lobyte = wParam And &HFF& End Function

Sub SocketsCleanup Dim lReturn As Long lReturn = WSACleanup If lReturn <> 0 Then MsgBox "Socket error " & Trim$(Str$(lReturn)) & _ " occurred in Cleanup" End End If     End Sub

 Press the F5 key to run the project. The Hostname should be printed on the form.

Additional query words: vb5rel kbintluk

Keywords: kbhowto kbdownload kbwinsock kbfile kbsample KB154512

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