GetInterfaceInfo

Retrieves information about the network interfaces on the local computer.

Syntax


ULONG GetInterfaceInfo(
  [out]     PIP_INTERFACE_INFO pIfTable,
  [in, out] PULONG             Size
);

Parameters

Parameter	Description
`pIfTable`	Pointer to a `NULL`-terminated array of `IP_INTERFACE_INFO` structures. This array receives the interface information. The buffer must be large enough to contain all the interface information.
`Size`	On input, the size of the buffer pointed to by `pIfTable`, in bytes. On output, if the function succeeds, this parameter is the size of the buffer used to store the interface information. If the buffer is not large enough to contain the returned interfaces, the function sets this parameter to the required buffer size in bytes, and returns `ERROR_INSUFFICIENT_BUFFER`.

Return Value

If the function succeeds, the return value is NO_ERROR.

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

Error Code	Description
`ERROR_INSUFFICIENT_BUFFER`	The buffer pointed to by `pIfTable` is not large enough to hold the interface information. The required size is returned in the `Size` parameter.
`ERROR_INVALID_PARAMETER`	One or more parameters are invalid.
`ERROR_NOT_SUPPORTED`	The operating system does not support this function.

Remarks

The GetInterfaceInfo function retrieves a table of all network interfaces on the local computer. This includes active interfaces, interfaces that are present but not currently active, and interfaces that are hidden. The information returned includes the interface's IP address, subnet mask, and the index of the interface.

The IP_INTERFACE_INFO structure contains information about a single network interface, including its description, IP address, and subnet mask.

To determine the correct buffer size required to receive all the interface information, call GetInterfaceInfo with a NULL pointer for pIfTable and 0 for the Size parameter. The function will return the required buffer size in the Size parameter. Then, allocate a buffer of that size and call the function again.

Important

This function is primarily used by applications that need to enumerate and query detailed information about network interfaces, such as network management tools or diagnostic utilities.

Requirements

Attribute	Value
Minimum supported client	Windows XP
Minimum supported server	Windows Server 2003
Header	`iphlpapi.h`
Library	`Iphlpapi.lib`
DLL	`Iphlpapi.dll`

Windows Documentation