WlanGetAvailableNetworkList function (wlanapi.h)
Note
Some information relates to pre-released product, which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Important
This API will be affected by upcoming changes to operating system behavior, planned for fall 2024. For more info, see Changes to API behavior for Wi-Fi access and location.
The WlanGetAvailableNetworkList function retrieves the list of available networks on a wireless LAN interface.
Syntax
DWORD WlanGetAvailableNetworkList(
[in] HANDLE hClientHandle,
[in] const GUID *pInterfaceGuid,
[in] DWORD dwFlags,
PVOID pReserved,
[out] PWLAN_AVAILABLE_NETWORK_LIST *ppAvailableNetworkList
);
Parameters
[in] hClientHandle
The client's session handle, obtained by a previous call to the WlanOpenHandle function.
[in] pInterfaceGuid
A pointer to the GUID of the wireless LAN interface to be queried.
The GUID of each wireless LAN interface enabled on a local computer can be determined using the WlanEnumInterfaces function.
[in] dwFlags
A set of flags that control the type of networks returned in the list. This parameter can be a combination of these possible values.
pReserved
Reserved for future use. This parameter must be set to NULL.
[out] ppAvailableNetworkList
A pointer to storage for a pointer to receive the returned list of visible networks in a WLAN_AVAILABLE_NETWORK_LIST structure.
The buffer for the WLAN_AVAILABLE_NETWORK_LIST returned is allocated by the WlanGetAvailableNetworkList function if the call succeeds.
Return value
If the function succeeds, the return value is ERROR_SUCCESS.
If the function fails, the return value may be one of the following return codes.
| Return code | Description |
|---|---|
|
A parameter is incorrect. This error is returned if the hClientHandle, pInterfaceGuid, or ppAvailableNetworkList parameter is NULL. This error is returned if the pReserved is not NULL. This error is also returned if the dwFlags parameter value is set to value that is not valid or the hClientHandle parameter is not valid. |
|
The handle hClientHandle was not found in the handle table. |
|
The radio associated with the interface is turned off. There are no available networks when the radio is off. |
|
Various error codes. |
|
Not enough memory is available to process this request and allocate memory for the query results. |
Remarks
The WlanGetAvailableNetworkList function allocates memory for the list of available networks returned in the buffer pointed to by the ppAvailableNetworkList parameter when the function succeeds. The memory used for the buffer pointed to by ppAvailableNetworkList parameter should be released by calling the WlanFreeMemory function after the buffer is no longer needed.
There is a hotfix available for Wireless LAN API for Windows XP with SP2 that can help improve the performance of applications that call WlanFreeMemory and WlanGetAvailableNetworkList many times.
Examples
The following example enumerates the wireless LAN interfaces on the local computer, retrieves the list of available networks on each wireless LAN interface, and prints values from the retrieved WLAN_AVAILABLE_NETWORK_LIST that contains the WLAN_AVAILABLE_NETWORK entries.
#ifndef UNICODE
#define UNICODE
#endif
#include <windows.h>
#include <wlanapi.h>
#include <objbase.h>
#include <wtypes.h>
#include <stdio.h>
#include <stdlib.h>
// Need to link with Wlanapi.lib and Ole32.lib
#pragma comment(lib, "wlanapi.lib")
#pragma comment(lib, "ole32.lib")
int wmain()
{
// Declare and initialize variables.
HANDLE hClient = NULL;
DWORD dwMaxClient = 2; //
DWORD dwCurVersion = 0;
DWORD dwResult = 0;
DWORD dwRetVal = 0;
int iRet = 0;
WCHAR GuidString[39] = {0};
unsigned int i, j, k;
/* variables used for WlanEnumInterfaces */
PWLAN_INTERFACE_INFO_LIST pIfList = NULL;
PWLAN_INTERFACE_INFO pIfInfo = NULL;
PWLAN_AVAILABLE_NETWORK_LIST pBssList = NULL;
PWLAN_AVAILABLE_NETWORK pBssEntry = NULL;
int iRSSI = 0;
dwResult = WlanOpenHandle(dwMaxClient, NULL, &dwCurVersion, &hClient);
if (dwResult != ERROR_SUCCESS) {
wprintf(L"WlanOpenHandle failed with error: %u\n", dwResult);
return 1;
// You can use FormatMessage here to find out why the function failed
}
dwResult = WlanEnumInterfaces(hClient, NULL, &pIfList);
if (dwResult != ERROR_SUCCESS) {
wprintf(L"WlanEnumInterfaces failed with error: %u\n", dwResult);
return 1;
// You can use FormatMessage here to find out why the function failed
} else {
wprintf(L"Num Entries: %lu\n", pIfList->dwNumberOfItems);
wprintf(L"Current Index: %lu\n", pIfList->dwIndex);
for (i = 0; i < (int) pIfList->dwNumberOfItems; i++) {
pIfInfo = (WLAN_INTERFACE_INFO *) &pIfList->InterfaceInfo[i];
wprintf(L" Interface Index[%u]:\t %lu\n", i, i);
iRet = StringFromGUID2(pIfInfo->InterfaceGuid, (LPOLESTR) &GuidString,
sizeof(GuidString)/sizeof(*GuidString));
// For c rather than C++ source code, the above line needs to be
// iRet = StringFromGUID2(&pIfInfo->InterfaceGuid, (LPOLESTR) &GuidString,
// sizeof(GuidString)/sizeof(*GuidString));
if (iRet == 0)
wprintf(L"StringFromGUID2 failed\n");
else {
wprintf(L" InterfaceGUID[%d]: %ws\n",i, GuidString);
}
wprintf(L" Interface Description[%d]: %ws", i,
pIfInfo->strInterfaceDescription);
wprintf(L"\n");
wprintf(L" Interface State[%d]:\t ", i);
switch (pIfInfo->isState) {
case wlan_interface_state_not_ready:
wprintf(L"Not ready\n");
break;
case wlan_interface_state_connected:
wprintf(L"Connected\n");
break;
case wlan_interface_state_ad_hoc_network_formed:
wprintf(L"First node in a ad hoc network\n");
break;
case wlan_interface_state_disconnecting:
wprintf(L"Disconnecting\n");
break;
case wlan_interface_state_disconnected:
wprintf(L"Not connected\n");
break;
case wlan_interface_state_associating:
wprintf(L"Attempting to associate with a network\n");
break;
case wlan_interface_state_discovering:
wprintf(L"Auto configuration is discovering settings for the network\n");
break;
case wlan_interface_state_authenticating:
wprintf(L"In process of authenticating\n");
break;
default:
wprintf(L"Unknown state %ld\n", pIfInfo->isState);
break;
}
wprintf(L"\n");
dwResult = WlanGetAvailableNetworkList(hClient,
&pIfInfo->InterfaceGuid,
0,
NULL,
&pBssList);
if (dwResult != ERROR_SUCCESS) {
wprintf(L"WlanGetAvailableNetworkList failed with error: %u\n",
dwResult);
dwRetVal = 1;
// You can use FormatMessage to find out why the function failed
} else {
wprintf(L"WLAN_AVAILABLE_NETWORK_LIST for this interface\n");
wprintf(L" Num Entries: %lu\n\n", pBssList->dwNumberOfItems);
for (j = 0; j < pBssList->dwNumberOfItems; j++) {
pBssEntry =
(WLAN_AVAILABLE_NETWORK *) & pBssList->Network[j];
wprintf(L" Profile Name[%u]: %ws\n", j, pBssEntry->strProfileName);
wprintf(L" SSID[%u]:\t\t ", j);
if (pBssEntry->dot11Ssid.uSSIDLength == 0)
wprintf(L"\n");
else {
for (k = 0; k < pBssEntry->dot11Ssid.uSSIDLength; k++) {
wprintf(L"%c", (int) pBssEntry->dot11Ssid.ucSSID[k]);
}
wprintf(L"\n");
}
wprintf(L" BSS Network type[%u]:\t ", j);
switch (pBssEntry->dot11BssType) {
case dot11_BSS_type_infrastructure :
wprintf(L"Infrastructure (%u)\n", pBssEntry->dot11BssType);
break;
case dot11_BSS_type_independent:
wprintf(L"Infrastructure (%u)\n", pBssEntry->dot11BssType);
break;
default:
wprintf(L"Other (%lu)\n", pBssEntry->dot11BssType);
break;
}
wprintf(L" Number of BSSIDs[%u]:\t %u\n", j, pBssEntry->uNumberOfBssids);
wprintf(L" Connectable[%u]:\t ", j);
if (pBssEntry->bNetworkConnectable)
wprintf(L"Yes\n");
else {
wprintf(L"No\n");
wprintf(L" Not connectable WLAN_REASON_CODE value[%u]:\t %u\n", j,
pBssEntry->wlanNotConnectableReason);
}
wprintf(L" Number of PHY types supported[%u]:\t %u\n", j, pBssEntry->uNumberOfPhyTypes);
if (pBssEntry->wlanSignalQuality == 0)
iRSSI = -100;
else if (pBssEntry->wlanSignalQuality == 100)
iRSSI = -50;
else
iRSSI = -100 + (pBssEntry->wlanSignalQuality/2);
wprintf(L" Signal Quality[%u]:\t %u (RSSI: %i dBm)\n", j,
pBssEntry->wlanSignalQuality, iRSSI);
wprintf(L" Security Enabled[%u]:\t ", j);
if (pBssEntry->bSecurityEnabled)
wprintf(L"Yes\n");
else
wprintf(L"No\n");
wprintf(L" Default AuthAlgorithm[%u]: ", j);
switch (pBssEntry->dot11DefaultAuthAlgorithm) {
case DOT11_AUTH_ALGO_80211_OPEN:
wprintf(L"802.11 Open (%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
case DOT11_AUTH_ALGO_80211_SHARED_KEY:
wprintf(L"802.11 Shared (%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
case DOT11_AUTH_ALGO_WPA:
wprintf(L"WPA (%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
case DOT11_AUTH_ALGO_WPA_PSK:
wprintf(L"WPA-PSK (%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
case DOT11_AUTH_ALGO_WPA_NONE:
wprintf(L"WPA-None (%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
case DOT11_AUTH_ALGO_RSNA:
wprintf(L"RSNA (%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
case DOT11_AUTH_ALGO_RSNA_PSK:
wprintf(L"RSNA with PSK(%u)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
default:
wprintf(L"Other (%lu)\n", pBssEntry->dot11DefaultAuthAlgorithm);
break;
}
wprintf(L" Default CipherAlgorithm[%u]: ", j);
switch (pBssEntry->dot11DefaultCipherAlgorithm) {
case DOT11_CIPHER_ALGO_NONE:
wprintf(L"None (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
case DOT11_CIPHER_ALGO_WEP40:
wprintf(L"WEP-40 (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
case DOT11_CIPHER_ALGO_TKIP:
wprintf(L"TKIP (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
case DOT11_CIPHER_ALGO_CCMP:
wprintf(L"CCMP (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
case DOT11_CIPHER_ALGO_WEP104:
wprintf(L"WEP-104 (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
case DOT11_CIPHER_ALGO_WEP:
wprintf(L"WEP (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
default:
wprintf(L"Other (0x%x)\n", pBssEntry->dot11DefaultCipherAlgorithm);
break;
}
wprintf(L" Flags[%u]:\t 0x%x", j, pBssEntry->dwFlags);
if (pBssEntry->dwFlags) {
if (pBssEntry->dwFlags & WLAN_AVAILABLE_NETWORK_CONNECTED)
wprintf(L" - Currently connected");
if (pBssEntry->dwFlags & WLAN_AVAILABLE_NETWORK_HAS_PROFILE)
wprintf(L" - Has profile");
}
wprintf(L"\n");
wprintf(L"\n");
}
}
}
}
if (pBssList != NULL) {
WlanFreeMemory(pBssList);
pBssList = NULL;
}
if (pIfList != NULL) {
WlanFreeMemory(pIfList);
pIfList = NULL;
}
return dwRetVal;
}
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista, Windows XP with SP3 [desktop apps only] |
| Minimum supported server | Windows Server 2008 [desktop apps only] |
| Target Platform | Windows |
| Header | wlanapi.h (include Wlanapi.h) |
| Library | Wlanapi.lib |
| DLL | Wlanapi.dll |
| Redistributable | Wireless LAN API for Windows XP with SP2 |