◄Up► ◄Next► ◄Previous►
────────────────────────────────────────────────────────────────────────────
 
The new features for the 3.1 version of the network driver interface consist
primarily of:
 
♦  Saved Network Connections
 
♦  New Capability Bits
 
♦  New Return Values
 
♦  String Handling
 
♦  Handling Error Messages
 
♦  New Print, Connection, and Dialog Functions
 
♦  Default Shell Behavior
 
♦  Long Filename Interface
 
♦  Enhancements To The 3.1 MS-Net Driver
 
Drivers written to the Windows 3.0 level of functionality will be supplied
with reasonable defaults for all 3.1 features. If a network does not require
special support for any of the features the network driver may be written to
the 3.0 specification.
 
For more complete information about network drivers, see the chapter
◄Network Drivers►.
 
Saved Network Connections
 
Saved network connections are connections which are always automatically
connected when Windows boots. If the connection cannot be made, the drive is
still treated as connected, as if it were in the error state. The File
Manager will reconnect the drive if the user selects it. When the user
connects to a drive or printer, that connection is remembered as a permanent
connection. When the user disconnects a device through the disconnect
dialog, it is removed from the list of permanently connected devices.
 
Although error state and permanent devices can be reconnected from the File
Manager, the drives may not (generally will not) be valid for other Windows
applications. If Windows was unable to restore a permanant connection when
starting, the user will be warned.
 
Network drivers which implement (or stub) these functions will return a
specification version of 3.10 (0x030A) from when the WNNC_SPEC_VERSION
parameter is specified with the WNetGetCaps function.
 
New Capability Bits
 
The WNetGetCaps function now returns several new capability bits.
 
The WNNC_PRINTING index now includes WNNC_PRT_WriteJob (0x8000). This bit
indicates support of the WNetWriteJob function.
 
The WNNC_CONNECTION index now includes WNNC_CON_RestoreConnection (0x0020).
This bit indicates support of the WNetRestoreConnection function.
 
The WNNC_DEVICEMODE index has been renamed WNNC_DIALOG. The index includes
several values for dialog functions, including a value for WNetBrowseDialog.
Although a bit is reserved for WNetBrowseDialog under WNNC_DIALOG, the
WNNC_CONN_BrowseDialog bit (returned using WNNC_CONNECTION) must also be
supported for compatibility; they mean the same thing and must both be set
or clear.
 
The new WNNC_ADMIN (0x0009) index has been added to indicate support of long
file names and administration functions. In Windows 3.1, these are limited
to modifying directory icons (in the tree view) and getting notification of
directory manipulations.
 
The new WNNC_PRINTMGREXT (0x000B) index has been added to indicate support
for extended Print Manager capabilities.
 
New Return Values
 
The WNetGetConnection function now returns several new error values.
 
The WN_DEVICE_ERROR (0x0035) value specifies that a connection exists on the
given device, but that the connection is in an error state and should be
disconnected and reconnected before it is accessed again. Generally, the
shell will attempt to reconnect such devices by calling the
WNetRestoreConnection function.
 
The WN_CONNECTION_CLOSED (0x0036) value indicates that a permanently
maintained connection is defined for the device, but that the device is not
currently connected to any network resource. This return value is defined
for those network drivers that export the WNetRestoreConnection function.
The only way a permanent connection can be closed is if the device could not
be connected when starting up.
 
The WN_CONTINUE (0x000D) value is used by functions to indicate a situation
distinct from both WN_CANCELLED and WN_SUCCESS where the shell does not need
to post a message to the user.
 
String Handling
 
All strings passed to the network driver may be assumed to be ANSI strings.
Similarly, all strings returned by the network driver should be ANSI
strings. This is not a new feature.
 
Handling Error Messages
 
If appropriate, the shell will post error messages whenever an error is
reported by a network driver function. If the error value is WN_NET_ERROR,
the WNetGetError and WNetGetErrorText functions will be called to allow the
network driver to return a network specific error. If these two functions
fail or are not implemented, a generic message will be used instead. This
behavior will be standardized across all shell components. Some functions,
such as connection dialogs, are allowed to post their own messages as part
of processing the dialog box. The shell never posts error messages if the
return value is WN_SUCCESS, WN_CANCEL, or WN_CONTINUE unless otherwise
noted.
 
New Print, Connection, and Dialog Functions
 
There are the following new functions:
 
Function               Description
────────────────────────────────────────────────────────────────────────────
WNetWriteJob           Writes to an open print job
 
WNetRestoreConnection  Restores a connection to a network device
 
WNetConnectDialog      Displays a shell connection dialog box
 
WNetDisconnectDialog   Displays a shell disconnection dialog box
 
WNetConnectionDialog   Displays a connection dialog box
 
WNetViewQueueDialog    Display a queue viewing dialog box
 
WNetGetPropertyText    Adds buttons to a property dialog box
 
WNetPropertyDialog     Supports added buttons in the property dialog
 
WNetGetDirectoryType   Retrieves directory type
 
WNetDirectoryNotify    Notifies driver of operations on directories
 
For network drivers that provide user functions, the following ordinals are
reserved the user functions:
 
WNNC_ORD_UserStart      500
WNNC_ORD_UserEnd        599
 
The shell is guaranteed never to use ordinals in this range.
 
Default Shell Behavior
 
If a network driver does not support the new function calls (for example, it
is a Windows 3.0 network driver), Windows and the File Manager simulate a
new method of supporting permanent connections.
 
The default connection dialog includes a checkbox for making a connection
permanent. If the user makes a permanent connection, the device will be
added to a WIN.INI section called [Network]. The tag will be the local
device and the value will be the network resource. For security, passwords
will not be saved. The following example illustrates the new section:
 
[Network]
S:=\\USER2\SHELL
T:=\\TOOLSVR\DOSENV
U:=\\PYREX\USER
LPT1=\\WINDEV\PRINTER
 
When a device is disconnected, it is removed from the list of permanent
devices. The File Manager simulates the WNetGetConnection behavior of
returning a connection with a special status when it is listed in WIN.INI
but is not connected. The default connection dialogs allows the user to
"reconnect" a disconnected device which has a saved connection. The dialogs
also support disconnecting and reconnecting a device in an error state.
 
On startup, Windows enumerates devices saved in the [Network] section and
attempts to redirect them using WNetAddConnection. If a device is already
redirected, the redirection will not be overridden. If WNetAddConnection
returns WN_BAD_PASSWORD the user will be prompted to supply the password.
 
Network drivers which require their own connection dialogs or startup
restore function should attempt to duplicate the functionality of the
default behavior as closely as possible in order to provide consistency. To
maintain this consistency, network drivers should use the [Network] section.
The tags "A:" through "Z:" and all common MS-DOS device names ("LPT1",
"COM1", "PRN", etc) are reserved, including those not currently supported
for redirection. The network driver may define additional tags of its own.
 
Long Filename Interface
 
The Long Filename interface enables access to files with names that do not
fit the MS-DOS 8.3 filename convention on network drives.
 
There are the following functions:
 
Function           Description
────────────────────────────────────────────────────────────────────────────
LFNFindFirst       Searches for the first file with a matching name
 
LFNFindNext        Searches for the next file with a matching name
 
LFNFindClose       Ends the search for matching files
 
LFNGetAttributes   Retrieves file attributes
 
LFNSetAttributes   Sets file attributes
 
LFNCopy            Copies a file
 
LFNMove            Moves a file
 
LFNDelete          Deletes a file
 
LFNMKDir           Creates a directory
 
LFNRMDir           Removes a directory
 
LFNGetVolumeLabel  Retrieves the volume label
 
LFNSetVolumeLabel  Sets the volume label
 
LFNParse           Parses paths
 
LFNVolumeType      Specifies volume type
 
Typically, these functions are called only when a network drive with long
filenames is detected. In other words, they do not need to support local
drives. The exception is the LFNCopy function which must be able to copy to
or from any type of volume.
 
The return value is typically a MS-DOS error function (as returned from
MS-DOS functions when the carry flag is set, or from int 21h Function 59h,
Get Extended Error Information). If a function returns the special error
code 0xFFFF, then the network error message functions will be called to
retrieve error message text.
 
The maximum length of any long filename will be assumed to be 260 including
the terminator.
 
File attribute values are identical to MS-DOS file attribute fields.
 
Enhancements To The 3.1 MS-Net Driver
 
The 3.1 MS-Net driver implements the error state return value from the
WNetGetConnection function. All connection dialogs are the default shell
dialogs. In addition, a WIN.INI switch is added to [Network] to disable the
spooler queue viewing functions. This will allow better use of the MS-Net
driver with "somewhat compatible" networks. By disabling the spooler queue
query functions, the MS-Net driver may run without assuming NETBIOS as the
transport or SMB as the file sharing protocol. It will also allow the use of
the MS-Net driver with servers that do not correctly implement the splretq
SMB command, such as early versions of Xenix-Net.
 
If possible through Kernel, the MS-Net driver should implement checking of
open files when a device is disconnected.
 
                                      ♦