GetIpAddrTable

Retrieves a table that contains the IPv4 address information for the local computer.

Function

DWORD GetIpAddrTable(PMIB_IPADDRTABLE pIpAddrTable, PULONG pdwSize, BOOL bOrder);

Syntax

DWORD GetIpAddrTable(
  PMIB_IPADDRTABLE pIpAddrTable,
  PULONG pdwSize,
  BOOL bOrder
);

Parameters

Parameter Description
pIpAddrTable

A pointer to a MIB_IPADDRTABLE structure that receives the IP address table. The entries in the table are sorted in ascending order based on the dwIndex member.
pdwSize

On input, specifies the size, in bytes, of the buffer pointed to by pIpAddrTable.

On output, if the function succeeds and the buffer is large enough, this parameter is updated with the actual size of the structure.
bOrder

A boolean value that specifies whether the IP address entries in the table should be sorted.

If TRUE, the entries are sorted in ascending order based on the dwIndex member.

If FALSE, the order of the entries is not guaranteed.

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:

Remarks

The GetIpAddrTable function is used to retrieve a list of IP addresses configured on the local computer. This function is available on Windows 2000 and later.

The MIB_IPADDRTABLE structure contains an array of MIB_IPADDRROW structures, each representing an IP address configuration for an interface.

To get the most accurate information, it is recommended to call GetIpAddrTable twice. The first call is to get the required buffer size, and the second call with an allocated buffer fills the table.

Example


#include <winsock2.h>
#include <iphlpapi.h>
#include <stdio.h>

#pragma comment(lib, "iphlpapi.lib")
#pragma comment(lib, "ws2_32.lib")

int main() {
    ULONG ulSize = 0;
    MIB_IPADDRTABLE* pIpAddrTable = NULL;
    DWORD dwRetVal = 0;

    // Get the required buffer size
    dwRetVal = GetIpAddrTable(NULL, &ulSize, TRUE);
    if (dwRetVal == ERROR_INSUFFICIENT_BUFFER) {
        pIpAddrTable = (MIB_IPADDRTABLE*) malloc(sizeof(MIB_IPADDRTABLE) + ulSize); // Allocate memory
        if (pIpAddrTable == NULL) {
            printf("Error allocating memory\n");
            return 1;
        }
    } else {
        printf("Error calling GetIpAddrTable (first call): %d\n", dwRetVal);
        return 1;
    }

    // Get the IP address table
    dwRetVal = GetIpAddrTable(pIpAddrTable, &ulSize, TRUE);

    if (dwRetVal == NO_ERROR) {
        printf("Successfully retrieved IP Address Table\n");
        printf("Number of entries: %d\n\n", pIpAddrTable->dwNumEntries);
        for (DWORD i = 0; i < pIpAddrTable->dwNumEntries; i++) {
            char ipAddrStr[INET_ADDRSTRLEN];
            char maskAddrStr[INET_ADDRSTRLEN];

            // Convert IP address to string
            inet_ntop(AF_INET, &(pIpAddrTable->table[i].dwAddr), ipAddrStr, INET_ADDRSTRLEN);
            // Convert subnet mask to string
            inet_ntop(AF_INET, &(pIpAddrTable->table[i].dwMask), maskAddrStr, INET_ADDRSTRLEN);

            printf("Interface Index: %lu\n", pIpAddrTable->table[i].dwIndex);
            printf("IP Address: %s\n", ipAddrStr);
            printf("Subnet Mask: %s\n", maskAddrStr);
            printf("Broadcast Address: %s\n", inet_ntoa(*((struct in_addr*)&pIpAddrTable->table[i].dwBCastAddr)));
            printf("------------------------------------\n");
        }
    } else {
        printf("Error calling GetIpAddrTable (second call): %d\n", dwRetVal);
    }

    // Free allocated memory
    if (pIpAddrTable) {
        free(pIpAddrTable);
        pIpAddrTable = NULL;
    }

    return 0;
}

Requirements

Header: Iphlpapi.h

Library: Iphlpapi.lib

Minimum supported client: Windows 2000 Professional

Minimum supported server: Windows 2000 Server

Header file: ws2tcpip.h (for inet_ntop)

See Also