WNetOpenEnum

The WNetOpenEnum function starts an enumeration of network resources or existing connections.

DWORD WNetOpenEnum(
  DWORD dwScope,     // scope of enumeration
  DWORD dwType,      // resource types to list
  DWORD dwUsage,     // resource usage to list
  LPNETRESOURCE lpNetResource,
                     // pointer to resource structure
  LPHANDLE lphEnum   // pointer to enumeration handle buffer
);

Parameters

dwScope

Specifies the scope of the enumeration. This parameter can be one of the following values:

Value	Meaning
RESOURCE_CONNECTED	All currently connected resources (the dwUsage parameter is ignored).
RESOURCE_CONTEXT	Only resources in the network context of the caller (used for a Network Neighborhood view). The dwUsage parameter is ignored.
RESOURCE_GLOBALNET	All resources on the network.
RESOURCE_REMEMBERED	All remembered (persistent) connections (the dwUsage parameter is ignored).

dwType

Specifies the resource types to enumerate. This parameter can be a combination of the following values:

Value	Meaning
RESOURCETYPE_ANY	All resources (this value cannot be combined with RESOURCETYPE_DISK or RESOURCETYPE_PRINT).
RESOURCETYPE_DISK	All disk resources.
RESOURCETYPE_PRINT	All print resources.

If a network provider cannot distinguish between print and disk resources, it may enumerate all resources.

dwUsage

Specifies the resource usage to be enumerated. This parameter can be a combination of the following values:

Value	Meaning
0	All resources
RESOURCEUSAGE_CONNECTABLE	All connectable resources
RESOURCEUSAGE_CONTAINER	All container resources

This parameter is ignored if the dwScope parameter is not RESOURCE_GLOBALNET.

lpNetResource

Points to a NETRESOURCE structure specifying the container to enumerate.

If this parameter is NULL, the root of the network is assumed. Windows organizes a network as a hierarchy; the root is the topmost container in the network.

If this parameter is not NULL, it must point to a NETRESOURCE structure. This structure can be filled in by the application or be returned by a call to the WNetEnumResource function. The NETRESOURCE structure must specify a container resource; that is, the RESOURCEUSAGE_CONTAINER value must be specified in the dwUsage member.

To enumerate all network resources, an application can begin the enumeration by calling WNetOpenEnum with lpNetResource set to NULL and then use the returned handle with WNetEnumResource to enumerate resources. If one of the resources in the NETRESOURCE array returned by the WNetEnumResource function is a container resource, WNetOpenEnum can be used to open the resource for further enumeration.

If the dwScope parameter is not RESOURCE_GLOBALNET, this parameter must be NULL.

lphEnum

Points to a variable filled with an enumeration handle that can be used in a subsequent call to WNetEnumResource.

Return Values

If the function succeeds, the return value is NO_ERROR.

If the function fails, the return value is an error code. To get extended error information, call GetLastError. GetLastError may return one of the following error codes:

Value	Meaning
ERROR_NOT_CONTAINER	The lpNetResource parameter does not point to a container.
ERROR_INVALID_PARAMETER	Either the dwScope or dwType parameter is invalid, or there is a bad combination of parameters.
ERROR_NO_NETWORK	No network is present.
ERROR_EXTENDED_ERROR	A network-specific error occurred. To get a description of the error, use the WNetGetLastError function.

The function returns error codes for compatibility with Windows version 3.1. For compatibility with Windows NT, the function also sets the error code value returned by GetLastError.

Remarks

The exact interpretation of RESOURCE_CONTEXT in the dwScope parameter depends on the networks installed on the machine.

The WNetOpenEnum function is used to begin enumeration of the resources in a single container. The following examples show the hierarchical structure of a Microsoft LAN Manager network and a Novell Netware network:

LanMan (container, in this case the provider) 
  ACCOUNTING (container, in this case the domain) 
    \\ACCTSPAY (container, in this case the server) 
      PAYFILES (disk) 
      LASERJET (print) 
 
Netware (container, in this case the provider) 
  MARKETING (container, in this case the server) 
    SYS (disk, first one on any Netware server) 
    ANOTHERVOLUME (disk) 
    LASERJET (print)

Windows CE: The WNetOpenEnum function is called by the network browser application to create lists of available resources on the network.

Windows CE does not support the predefined value of RESOURCE_CONTEXT because a device cannot belong to a specific network context.

QuickInfo

  Windows NT: Use version 3.1 or later.
  Windows: Use Windows 95 or later.
  Windows CE: Use version 2.0 or later.
  Header: Declared in winnetwk.h.
  Import Library: Use mpr.lib.

WNetOpenEnum

Parameters

Return Values

Remarks

QuickInfo

See Also