Receiving Notification of Network Events
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4/8/2010
Use the following functions to ensure that an application receives notification of certain network events.
Note
These functions block the application until notification is received.
The NotifyAddrChange function enables an application to request notification of any change that occurs in the table that maps IP addresses to interfaces on the local computer.
Similarly, the NotifyRouteChange function enables an application to request notification of any change that occurs in the IP routing table.
The notifications provided by these functions do not specify what changed. They simply specify that something changed. Use other IP Helper functions to determine the exact nature of the change.
The following table describes each NotifyAddrChange variable and OVERLAPPED member.
| Value | Description |
|---|---|
Handle |
Pointer to a HANDLE variable that receives a handle to use in asynchronous notification. |
overlapped |
Pointer to an OVERLAPPED structure that will notify the caller of any changes in the table that maps IP addresses to interfaces. |
OVERLAPPED (structure) |
InternalHigh > [!NOTE] > Reserved for operating system use. This member, which specifies the length of the data transferred, is valid when the GetOverlappedResult function returns TRUE.Offset > [!NOTE] > Specifies a file position at which to start the transfer. The file position is a byte offset from the start of the file. The calling process sets this member before calling the ReadFile or WriteFile function.OffsetHigh > [!NOTE] > Specifies the high word of the byte offset at which to start the transfer.hEvent > [!NOTE] > Handle to an event set to the signaled state when the operation has been completed. The calling process must set this member either to zero or a valid event handle before calling any overlapped functions. To create an event object, use the CreateEvent function. |
The following table describes each NotifyRouteChange variable.
| Value | Description |
|---|---|
Handle |
Pointer to a HANDLE variable that receives a handle to use in asynchronous notification. |
overlapped |
Pointer to an OVERLAPPED structure that will notify the caller of any changes in the routing table. (See the NotifyAddrChange description above). |