GetAdaptersInfo function (iphlpapi.h)

The GetAdaptersInfo function retrieves adapter information for the local computer.

On Windows XP and later:  Use the GetAdaptersAddresses function instead of GetAdaptersInfo.

Syntax

IPHLPAPI_DLL_LINKAGE ULONG GetAdaptersInfo(
  [out]     PIP_ADAPTER_INFO AdapterInfo,
  [in, out] PULONG           SizePointer
);

Parameters

[out] AdapterInfo

A pointer to a buffer that receives a linked list of IP_ADAPTER_INFO structures.

[in, out] SizePointer

A pointer to a ULONG variable that specifies the size of the buffer pointed to by the pAdapterInfo parameter. If this size is insufficient to hold the adapter information, GetAdaptersInfo fills in this variable with the required size, and returns an error code of ERROR_BUFFER_OVERFLOW.

Return value

If the function succeeds, the return value is ERROR_SUCCESS (defined to the same value as NO_ERROR).

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

Remarks

The GetAdaptersInfo function can retrieve information only for IPv4 addresses.

In versions prior to Windows 10, the order in which adapters appear in the list returned by this function can be controlled from the Network Connections folder: select the Advanced Settings menu item from the Advanced menu. Starting with Windows 10, the order is unspecified.

The GetAdaptersInfo and GetInterfaceInfo functions do not return information about the IPv4 loopback interface. Information on the loopback interface is returned by the GetIpAddrTable function.

On Windows XP and later:  The list of adapters returned by GetAdaptersInfo includes unidirectional adapters. To generate a list of adapters that can both send and receive data, call GetUniDirectionalAdapterInfo, and exclude the returned adapters from the list returned by GetAdaptersInfo.

Examples

This example retrieves the adapter information and prints various properties of each adapter.

#include <winsock2.h>
#include <iphlpapi.h>
#include <stdio.h>
#include <stdlib.h>
#pragma comment(lib, "IPHLPAPI.lib")

#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x))
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))

/* Note: could also use malloc() and free() */

int __cdecl main()
{

    /* Declare and initialize variables */

// It is possible for an adapter to have multiple
// IPv4 addresses, gateways, and secondary WINS servers
// assigned to the adapter. 
//
// Note that this sample code only prints out the 
// first entry for the IP address/mask, and gateway, and
// the primary and secondary WINS server for each adapter. 

    PIP_ADAPTER_INFO pAdapterInfo;
    PIP_ADAPTER_INFO pAdapter = NULL;
    DWORD dwRetVal = 0;
    UINT i;

/* variables used to print DHCP time info */
    struct tm newtime;
    char buffer[32];
    errno_t error;

    ULONG ulOutBufLen = sizeof (IP_ADAPTER_INFO);
    pAdapterInfo = (IP_ADAPTER_INFO *) MALLOC(sizeof (IP_ADAPTER_INFO));
    if (pAdapterInfo == NULL) {
        printf("Error allocating memory needed to call GetAdaptersinfo\n");
        return 1;
    }
// Make an initial call to GetAdaptersInfo to get
// the necessary size into the ulOutBufLen variable
    if (GetAdaptersInfo(pAdapterInfo, &ulOutBufLen) == ERROR_BUFFER_OVERFLOW) {
        FREE(pAdapterInfo);
        pAdapterInfo = (IP_ADAPTER_INFO *) MALLOC(ulOutBufLen);
        if (pAdapterInfo == NULL) {
            printf("Error allocating memory needed to call GetAdaptersinfo\n");
            return 1;
        }
    }

    if ((dwRetVal = GetAdaptersInfo(pAdapterInfo, &ulOutBufLen)) == NO_ERROR) {
        pAdapter = pAdapterInfo;
        while (pAdapter) {
            printf("\tComboIndex: \t%d\n", pAdapter->ComboIndex);
            printf("\tAdapter Name: \t%s\n", pAdapter->AdapterName);
            printf("\tAdapter Desc: \t%s\n", pAdapter->Description);
            printf("\tAdapter Addr: \t");
            for (i = 0; i < pAdapter->AddressLength; i++) {
                if (i == (pAdapter->AddressLength - 1))
                    printf("%.2X\n", (int) pAdapter->Address[i]);
                else
                    printf("%.2X-", (int) pAdapter->Address[i]);
            }
            printf("\tIndex: \t%d\n", pAdapter->Index);
            printf("\tType: \t");
            switch (pAdapter->Type) {
            case MIB_IF_TYPE_OTHER:
                printf("Other\n");
                break;
            case MIB_IF_TYPE_ETHERNET:
                printf("Ethernet\n");
                break;
            case MIB_IF_TYPE_TOKENRING:
                printf("Token Ring\n");
                break;
            case MIB_IF_TYPE_FDDI:
                printf("FDDI\n");
                break;
            case MIB_IF_TYPE_PPP:
                printf("PPP\n");
                break;
            case MIB_IF_TYPE_LOOPBACK:
                printf("Loopback\n");
                break;
            case MIB_IF_TYPE_SLIP:
                printf("Slip\n");
                break;
            default:
                printf("Unknown type %ld\n", pAdapter->Type);
                break;
            }

            printf("\tIP Address: \t%s\n",
                   pAdapter->IpAddressList.IpAddress.String);
            printf("\tIP Mask: \t%s\n", pAdapter->IpAddressList.IpMask.String);

            printf("\tGateway: \t%s\n", pAdapter->GatewayList.IpAddress.String);
            printf("\t***\n");

            if (pAdapter->DhcpEnabled) {
                printf("\tDHCP Enabled: Yes\n");
                printf("\t  DHCP Server: \t%s\n",
                       pAdapter->DhcpServer.IpAddress.String);

                printf("\t  Lease Obtained: ");
                /* Display local time */
                error = _localtime32_s(&newtime, (__time32_t*) &pAdapter->LeaseObtained);
                if (error)
                    printf("Invalid Argument to _localtime32_s\n");
                else {
                    // Convert to an ASCII representation 
                    error = asctime_s(buffer, 32, &newtime);
                    if (error)
                        printf("Invalid Argument to asctime_s\n");
                    else
                        /* asctime_s returns the string terminated by \n\0 */
                        printf("%s", buffer);
                }

                printf("\t  Lease Expires:  ");
                error = _localtime32_s(&newtime, (__time32_t*) &pAdapter->LeaseExpires);
                if (error)
                    printf("Invalid Argument to _localtime32_s\n");
                else {
                    // Convert to an ASCII representation 
                    error = asctime_s(buffer, 32, &newtime);
                    if (error)
                        printf("Invalid Argument to asctime_s\n");
                    else
                        /* asctime_s returns the string terminated by \n\0 */
                        printf("%s", buffer);
                }
            } else
                printf("\tDHCP Enabled: No\n");

            if (pAdapter->HaveWins) {
                printf("\tHave Wins: Yes\n");
                printf("\t  Primary Wins Server:    %s\n",
                       pAdapter->PrimaryWinsServer.IpAddress.String);
                printf("\t  Secondary Wins Server:  %s\n",
                       pAdapter->SecondaryWinsServer.IpAddress.String);
            } else
                printf("\tHave Wins: No\n");
            pAdapter = pAdapter->Next;
            printf("\n");
        }
    } else {
        printf("GetAdaptersInfo failed with error: %d\n", dwRetVal);

    }
    if (pAdapterInfo)
        FREE(pAdapterInfo);

    return 0;
}

Requirements

See also

GetAdaptersAddresses

GetInterfaceInfo

GetIpAddrTable

GetNumberOfInterfaces

GetUniDirectionalAdapterInfo

IP Helper Function Reference

IP Helper Start Page

IP_ADAPTER_INFO