Microsoft KB Archive/239561

= How To Use CoInitializeSecurity in Visual Basic =

Article ID: 239561

Article Last Modified on 7/13/2004

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APPLIES TO


 * Microsoft Visual Basic 5.0 Learning Edition
 * Microsoft Visual Basic 6.0 Learning Edition
 * 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

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This article was previously published under Q239561



SUMMARY
The CoInitializeSecurity function can be used to set security values for a process. There are some restrictions that must be considered when calling this function from a Visual Basic application.



MORE INFORMATION
The CoInitializeSecurity function must be called at the very beginning of your Visual Basic program and before any type of marshalling is performed. If you are developing an ActiveX Server application such as an ActiveX EXE, there is no way to successfully call CoInitializeSecurity because marshalling has already been performed when your application gets control. When calling CoInitializeSecurity from a Standard EXE project, you must start your application with a Sub Main and the call must be made at the very beginning of the procedure. Another point to consider is that a call to CoInitializeSecurity only succeeds in the compiled executable. When running an application in the IDE, the function call fails because marshalling has already occurred for the Visual Basic process and therefore it is already too late to make the call. To work around this, use a conditional compilation block when making the function call as shown here.  Open a Standard EXE project. Form1 is created by default. From the Project menu, add a new module and create a Sub Main. From the Project menu, choose Project1 Properties and define Sub Main as the start-up procedure.  Include the following Sample Code in the bas module: Option Explicit

' Authentication service provider constants ' the default should be used. Private Const RPC_C_AUTHN_NONE                 As Long = 0 Private Const RPC_C_AUTHN_WINNT                As Long = 10 Private Const RPC_C_AUTHN_DEFAULT              As Long = &HFFFFFFFF

' Authentication level constants Private Const RPC_C_AUTHN_LEVEL_DEFAULT        As Long = 0 Private Const RPC_C_AUTHN_LEVEL_NONE           As Long = 1 Private Const RPC_C_AUTHN_LEVEL_CONNECT        As Long = 2 Private Const RPC_C_AUTHN_LEVEL_CALL           As Long = 3 Private Const RPC_C_AUTHN_LEVEL_PKT            As Long = 4 Private Const RPC_C_AUTHN_LEVEL_PKT_INTEGRITY  As Long = 5 Private Const RPC_C_AUTHN_LEVEL_PKT_PRIVACY    As Long = 6

' Impersonation level constants Private Const RPC_C_IMP_LEVEL_ANONYMOUS        As Long = 1 Private Const RPC_C_IMP_LEVEL_IDENTIFY         As Long = 2 Private Const RPC_C_IMP_LEVEL_IMPERSONATE      As Long = 3 Private Const RPC_C_IMP_LEVEL_DELEGATE         As Long = 4

' Constants for the capabilities Private Const API_NULL                         As Long = 0 Private Const S_OK                             As Long = 0 Private Const EOAC_NONE                        As Long = &H0 Private Const EOAC_MUTUAL_AUTH                 As Long = &H1 Private Const EOAC_CLOAKING                    As Long = &H10 Private Const EOAC_SECURE_REFS                 As Long = &H2 Private Const EOAC_ACCESS_CONTROL              As Long = &H4 Private Const EOAC_APPID                       As Long = &H8

' Function Declaration Private Declare Function CoInitializeSecurity Lib "OLE32.DLL" ( _ pSD As Any, _ ByVal cAuthSvc As Long, _ asAuthSvc As Long, _ pReserved1 As Any, _ ByVal dwAuthnlevel As Long, _ ByVal dwImpLevel As Long, _ ByVal pAuthInfo As Long, _ ByVal dwCapabilities As Long, _ pvReserved2 As Any _ ) As Long

Sub Main ' This must be called in the executable only. ' It will fail in the IDE. To avoid any problem, ' include it in a conditional compilation block. #If RUN_IN_IDE Then Msgbox "You are running in the IDE" #else Dim lngHr As Long Dim lngAuthn As Long lngAuthn = RPC_C_AUTHN_DEFAULT lngHr = CoInitializeSecurity(ByVal API_NULL, -1, _       lngAuthn, ByVal API_NULL, _        RPC_C_AUTHN_LEVEL_NONE, RPC_C_IMP_LEVEL_ANONYMOUS, _        API_NULL, EOAC_NONE, ByVal API_NULL) If (S_OK <> lngHr) Then MsgBox "CoInitializeSecurity failed with error code: 0x" _ & Trim$(Str$(Hex(lngHr))), vbCritical, _ "Application Initialization Failure" Exit Sub End If   #End If ' RUN_IN_IDE ' Any additional code you need here. Form1.Show ' showing your starting form End Sub  Make and run the executable.NOTE: If you choose to run the application in the IDE, you must define the RUN_IN_IDE constant as TRUE.

Do this as follows:

From the Project, menu select Project1 Properties and click the Make tab. In the Conditional Compilation Arguments field, enter RUN_IN_IDE = -1.

Be sure to remove the above Conditional Compilation Argument "RUN_IN_IDE" when making the executable.

Keywords: kbhowto kbapi KB239561

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