Note
Access to this page requires authorization. You can try signing in or changing directories.
Access to this page requires authorization. You can try changing directories.
To enumerate the battery devices on a local computer, use the SetupDiGetClassDevs function. The ClassGuid parameter is a pointer to GUID_DEVCLASS_BATTERY (defined in BatClass.h). To enumerate all of the batteries, set the Enumerator parameter to NULL and set the Flags parameter to DIGCF_PRESENT | DIGCF_INTERFACEDEVICE. To obtain the names of the battery devices, use the SetupDiEnumDeviceInterfaces and SetupDiGetDeviceInterfaceDetail functions on the data returned. To open a file handle for each of the battery devices, call the CreateFile function with these names.
The following C++ example shows how to enumerate battery devices on a local computer.
DWORD GetBatteryState()
{
#define GBS_HASBATTERY 0x1
#define GBS_ONBATTERY 0x2
// Returned value includes GBS_HASBATTERY if the system has a
// non-UPS battery, and GBS_ONBATTERY if the system is running on
// a battery.
//
// dwResult & GBS_ONBATTERY means we have not yet found AC power.
// dwResult & GBS_HASBATTERY means we have found a non-UPS battery.
DWORD dwResult = GBS_ONBATTERY;
// IOCTL_BATTERY_QUERY_INFORMATION,
// enumerate the batteries and ask each one for information.
HDEVINFO hdev =
SetupDiGetClassDevs(&GUID_DEVCLASS_BATTERY,
0,
0,
DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
if (INVALID_HANDLE_VALUE != hdev)
{
// Limit search to 100 batteries max
for (int idev = 0; idev < 100; idev++)
{
SP_DEVICE_INTERFACE_DATA did = {0};
did.cbSize = sizeof(did);
if (SetupDiEnumDeviceInterfaces(hdev,
0,
&GUID_DEVCLASS_BATTERY,
idev,
&did))
{
DWORD cbRequired = 0;
SetupDiGetDeviceInterfaceDetail(hdev,
&did,
0,
0,
&cbRequired,
0);
if (ERROR_INSUFFICIENT_BUFFER == GetLastError())
{
PSP_DEVICE_INTERFACE_DETAIL_DATA pdidd =
(PSP_DEVICE_INTERFACE_DETAIL_DATA)LocalAlloc(LPTR,
cbRequired);
if (pdidd)
{
pdidd->cbSize = sizeof(*pdidd);
if (SetupDiGetDeviceInterfaceDetail(hdev,
&did,
pdidd,
cbRequired,
&cbRequired,
0))
{
// Enumerated a battery. Ask it for information.
HANDLE hBattery =
CreateFile(pdidd->DevicePath,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
if (INVALID_HANDLE_VALUE != hBattery)
{
// Ask the battery for its tag.
BATTERY_QUERY_INFORMATION bqi = {0};
DWORD dwWait = 0;
DWORD dwOut;
if (DeviceIoControl(hBattery,
IOCTL_BATTERY_QUERY_TAG,
&dwWait,
sizeof(dwWait),
&bqi.BatteryTag,
sizeof(bqi.BatteryTag),
&dwOut,
NULL)
&& bqi.BatteryTag)
{
// With the tag, you can query the battery info.
BATTERY_INFORMATION bi = {0};
bqi.InformationLevel = BatteryInformation;
if (DeviceIoControl(hBattery,
IOCTL_BATTERY_QUERY_INFORMATION,
&bqi,
sizeof(bqi),
&bi,
sizeof(bi),
&dwOut,
NULL))
{
// Only non-UPS system batteries count
if (bi.Capabilities & BATTERY_SYSTEM_BATTERY)
{
if (!(bi.Capabilities & BATTERY_IS_SHORT_TERM))
{
dwResult |= GBS_HASBATTERY;
}
// Query the battery status.
BATTERY_WAIT_STATUS bws = {0};
bws.BatteryTag = bqi.BatteryTag;
BATTERY_STATUS bs;
if (DeviceIoControl(hBattery,
IOCTL_BATTERY_QUERY_STATUS,
&bws,
sizeof(bws),
&bs,
sizeof(bs),
&dwOut,
NULL))
{
if (bs.PowerState & BATTERY_POWER_ON_LINE)
{
dwResult &= ~GBS_ONBATTERY;
}
}
}
}
}
CloseHandle(hBattery);
}
}
LocalFree(pdidd);
}
}
}
else if (ERROR_NO_MORE_ITEMS == GetLastError())
{
break; // Enumeration failed - perhaps we're out of items
}
}
SetupDiDestroyDeviceInfoList(hdev);
}
// Final cleanup: If we didn't find a battery, then presume that we
// are on AC power.
if (!(dwResult & GBS_HASBATTERY))
dwResult &= ~GBS_ONBATTERY;
return dwResult;
}
To enumerate the battery devices connected to a remote computer, use the Win32_Battery WMI class in a client script or application.
Related topics