DhcpEnumSubnetClientsV4 function (dhcpsapi.h)

The DhcpEnumSubnetClientsV4 function returns an enumerated list of client lease records with served IP addresses in the specified subnet. This function extends the functionality provided in DhcpEnumSubnetClients by returning a list of DHCP_CLIENT_INFO_V4 structures that contain the specific client type (DHCP and/or BOOTP).

Syntax

DWORD DHCP_API_FUNCTION DhcpEnumSubnetClientsV4(
  [in]      DHCP_CONST WCHAR            *ServerIpAddress,
  [in]      DHCP_IP_ADDRESS             SubnetAddress,
  [in, out] DHCP_RESUME_HANDLE          *ResumeHandle,
  [in]      DWORD                       PreferredMaximum,
  [out]     LPDHCP_CLIENT_INFO_ARRAY_V4 *ClientInfo,
  [out]     DWORD                       *ClientsRead,
  [out]     DWORD                       *ClientsTotal
);

Parameters

[in] ServerIpAddress

Unicode string that specifies the IP address or hostname of the DHCP server.

[in] SubnetAddress

DHCP_IP_ADDRESS value containing the IP address of the subnet gateway.

[in, out] ResumeHandle

Pointer to a DHCP_RESUME_HANDLE value that identifies the enumeration operation. Initially, this value should be zero, with a successful call returning the handle value used for subsequent enumeration requests. This parameter contains the last last IPv4 address retrieved from the DHCPv4 client.

The presence of additional enumerable data is indicated when this function returns ERROR_MORE_DATA. If no additional enumerable data is available on the DHCPv4 server, ERROR_NO_MORE_ITEMS is returned.

[in] PreferredMaximum

Specifies the preferred maximum number of bytes of subnet client elements to return. If the number of remaining unenumerated elements (in bytes) is less than this value, then that amount will be returned. The minimum value is 1024 bytes, and the maximum value is 65536 bytes.

To retrieve all the subnet client elements for the default user and vendor class at the specified level, set this parameter to 0xFFFFFFFF.

[out] ClientInfo

Pointer to a DHCP_CLIENT_INFO_ARRAY_V4 structure that contains the DHCPv4 client lease record array. If no clients are available, this field will be null.

[out] ClientsRead

Pointer to a DWORD value that specifies the number of client lease records returned in ClientInfo.

[out] ClientsTotal

Pointer to a DWORD value that specifies the total number of client lease records remaining on the DHCPv4 server. For example, if there are 100 DHCPv4 lease records for an IPv4 subnet, and if 10 DHCPv4 lease records are enumerated per call, then this parameter would return a value of 90 after the first call.

Return value

This function returns ERROR_SUCCESS upon a successful call. Otherwise, it returns one of the DHCP Server Management API Error Codes.

Return code Description
ERROR_DHCP_JET_ERROR
An error occurred while accessing the DHCP server database.
ERROR_MORE_DATA
There are more elements available to enumerate.
ERROR_NO_MORE_ITEMS
There are no more elements left to enumerate.
ERROR_DHCP_SUBNET_NOT_PRESENT
The specified IPv4 subnet does not exist on the DHCP server.

Remarks

The caller of this function must free the memory for ClientInfo after the call completes.

Requirements

   
Minimum supported client None supported
Minimum supported server Windows Server 2008 R2 [desktop apps only]
Target Platform Windows
Header dhcpsapi.h
Library Dhcpsapi.lib
DLL Dhcpsapi.dll

See also

DHCP_CLIENT_INFO_ARRAY_V4

DhcpEnumSubnetClients

DhcpEnumSubnetClientsV5