WNetUseConnection

The WNetUseConnection function makes a connection to a network resource. The function can redirect a local device to the network resource.

The WNetUseConnection function is similar to the WNetAddConnection3 function. The main difference is that WNetUseConnection can automatically select an unused local device to be redirected to the network resource.

Windows 95:
For Windows 95, the lpUserName and lpPassword parameters are in reverse order from those in the Windows NT version as follows:

DWORD WNetUseConnection(
  HWND hwndOwner,               
  LPNETRESOURCE lpNetResource,  
  LPTSTR lpUserName,            
  LPTSTR lpPassword,            
  DWORD dwFlags,                
  LPTSTR lpAccessName,          
  LPDWORD lpBufferSize,         
  LPDWORD lpResult              
);
 

For Windows NT the parameter order is as follows:

DWORD WNetUseConnection(
  HWND hwndOwner,               
  LPNETRESOURCE lpNetResource,  
  LPTSTR lpPassword,            
  LPTSTR lpUserName,            
  DWORD dwFlags,                
  LPTSTR lpAccessName,          
  LPDWORD lpBufferSize,         
  LPDWORD lpResult              
);
 

Parameters

hwndOwner
Specifies a window that the provider of network resources can use as an owner window for dialog boxes. Use this parameter if CONNECT_INTERACTIVE is set.
lpNetResource
Pointer to a NETRESOURCE structure that specifies details of the proposed connection. The structure contains information about the network resource, the local device, and the network resource provider.

You must specify the following members of the NETRESOURCE structure:
Member Description
dwType Specifies the type of resource to connect to. It is most efficient to use a specific resource type (such as RESOURCETYPE_DISK or RESOURCETYPE_PRINT). However, if lpLocalName is NULL or points to an empty string and CONNECT_REDIRECT is not set, dwType can be RESOURCETYPE_ANY. This method works only if the function does not automatically choose a device to redirect to the network resource.
lpLocalName Points to a null-terminated string that specifies the name of a local device to be redirected, such as "F:" or "LPT1." The string is treated in a case-insensitive manner. If the string is empty or if lpLocalName is NULL, a connection to the network occurs without redirection. If CONNECT_REDIRECT is set or the network requires a redirected local device, the function chooses a local device to redirect and returns the name of the device in lpAccessName.
lpRemoteName Points to a null-terminated string that specifies the network resource to connect to. The string can be up to MAX_PATH characters in length. The string must follow the network provider's naming conventions.
lpProvider Points to a null-terminated string that specifies the network provider to connect to. If lpProvider is NULL or points to an empty string, the operating system attempts to determine the correct provider by parsing the string pointed to by lpRemoteName.
You should set this member only if you know for certain which network provider you want to use. Otherwise, let the operating system determine which network provider the network name maps to.
If this member is not NULL, the operating system attempts to make a connection only to the named network provider.

The WNetUseConnection function ignores the other members of the NETRESOURCE structure.

lpPassword
Pointer to a null-terminated string that specifies a password to be used in making the network connection.

If lpPassword is NULL, the function uses the current default password associated with the user specified by lpUserName.

If lpPassword points to an empty string, the function does not use a password.

If the connection fails because of an invalid password and CONNECT_INTERACTIVE is set, the function displays a dialog box asking the user to type the password.

lpUserName
Pointer to a null-terminated string that specifies a user name to be used in making the connection.

If lpUserName is NULL, the function uses the default user name. The user context for the process provides the default user name.

The lpUserName parameter is specified when users want to connect to a network resource for which they have been assigned a user name or account other than the default user name or account.

The user-name string represents a security context. It may be specific to a network provider.

dwFlags
Specifies any combination of the following values:
Value Meaning
CONNECT_INTERACTIVE If this flag is set, the operating system may interact with the user for authentication purposes.
CONNECT_PROMPT This flag instructs the system not to use any default settings for user names or passwords without offering the user the chance to supply an alternative. This flag is ignored unless CONNECT_INTERACTIVE is set.
CONNECT_REDIRECT This flag forces the redirection of a local device when making the connection. If lpLocalName specifies a local device to redirect, this flag has no effect, because the operating system attempts to redirect the specified device anyway. Otherwise, if the operating system automatically chooses a local device, lpAccessName must point to a return buffer and dwType must not be RESOURCETYPE_ANY.

If this flag is not set, a local device is automatically chosen for redirection only if the network requires a local device to be redirected.

CONNECT_UPDATE_PROFILE This flag instructs the operating system to store the network resource connection.

If this bit flag is set, the operating system automatically attempts to restore the connection when the user logs on. The system remembers only successful connections that redirect local devices. It does not remember unsuccessful connections and deviceless connections. A deviceless connection occurs when lpLocalName is NULL or points to an empty string.

If this bit flag is clear, the operating system will not automatically restore the connection at logon.


lpAccessName
Specifies the name of a buffer that receives system requests on the connection.

If lpLocalName specifies a local device, this buffer is optional, and will have the local device name copied into it. If lpLocalName does not specify a device and the network requires a local device redirection, or if CONNECT_REDIRECT is set, this buffer is required and the name of the redirected local device is returned here. Otherwise, the name copied into the buffer is that of a remote resource. If specified, this buffer must be at least as large as the string pointed to by the lpRemoteName parameter.

lpBufferSize
Specifies the size, in characters, of the lpAccessName buffer passed in. If the call fails because the buffer is not large enough, the function uses this location to return the required buffer size.
lpResult
Pointer to a DWORD that returns additional information about the connection. This parameter can be a combination of the following values:
Value Meaning
CONNECT_LOCALDRIVE If this flag is set, the connection was made using a local device redirection. If the lpAccessName parameter points to a buffer, the local device name is copied to the buffer.

Return Values

If the function succeeds, the return value is NO_ERROR.

If the function fails, the return value is one of the following error codes.

Value Meaning
ERROR_ACCESS_DENIED Access to the network resource was denied.
ERROR_ALREADY_ASSIGNED The local device specified by lpLocalName is already connected to a network resource.
ERROR_BAD_DEVICE The value specified by lpLocalName is invalid.
ERROR_BAD_NET_NAME The value specified by lpRemoteName is not acceptable to any network resource provider. The resource name is invalid, or the named resource cannot be located.
ERROR_BAD_PROVIDER The value specified by lpProvider does not match any provider.
ERROR_CANCELLED The attempt to make the connection was canceled by the user through a dialog box from one of the network resource providers or by a called resource.
ERROR_EXTENDED_ERROR A network-specific error occurred. To get a description of the error, call the WNetGetLastError function.
ERROR_INVALID_ADDRESS The caller passed in a pointer to a buffer that could not be accessed.
ERROR_INVALID_PARAMETER This error is a result of one of the following conditions:
  1. The lpRemoteName member is NULL; lpAccessName is not NULL, but lpBufferSize is either NULL or points to zero.
  2. The dwType member is neither RESOURCETYPE_DISK nor RESOURCETYPE_PRINT. In addition, CONNECT_REDIRECT is set in dwFlags, lpLocalName is NULL, or the connection is to a network that requires the redirecting of a local device.
ERROR_INVALID_PASSWORD The specified password is invalid and CONNECT_INTERACTIVE is not set.
ERROR_MORE_DATA The lpAccessName buffer is too small. If a local device is redirected, the buffer needs to be large enough to contain the local device name. Otherwise, the buffer needs to be large enough to contain either the string pointed to by lpRemoteName or the name of the connectable resource whose alias is pointed to by lpRemoteName. If this status is returned, then no connection has been made.
ERROR_NO_MORE_ITEMS The operating system cannot automatically choose a local redirection because all the valid local devices are in use.
ERROR_NO_NET_OR_BAD_PATH A network component has not started, or the specified name could not be handled.
ERROR_NO_NETWORK There is no network present.

QuickInfo

  Windows NT: Use version 3.1 or later.
  Windows: Use Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in winnetwk.h.
  Import Library: Use mpr.lib.

See Also

Windows Networking (WNet) Overview, Windows Networking Functions, WNetAddConnection, WNetAddConnection2, WNetAddConnection3, WnetCancelConnection, WNetGetConnection, WNetGetLastError