I'm taking my first steps in Delphi, I've created a small program that uses the GetSystemPowerStatus function to get battery status information.

To load the function, I used the Winapi.Windows unit.

Everything worked fine, but the EXE file after compilation took up 150 kb.

From what I understand from this post, using the Winapi.Windows unit is the cause of the increase, but I have not found how to access the GetSystemPowerStatus function without using the unit.

Is this possible, and how can it be done?

CodePudding user response：

If you don't want to use the Winapi.Windows unit, you will just have to declare the function in your own code. See Importing Functions from Libraries in Delphi's documentation.

For example:

type
  SYSTEM_POWER_STATUS = record
    ACLineStatus: Byte;
    BatteryFlag: Byte;
    BatteryLifePercent: Byte;
    SystemStatusFlag: Byte;
    BatteryLifeTime: UInt32;
    BatteryFullLifeTime: UInt32;
  end; 

function GetSystemPowerStatus(var lpSystemPowerStatus: SYSTEM_POWER_STATUS): LongBool; stdcall; external 'Kernel32';

This is similar (but different) to how the Winapi.Windows unit declares the function. The main differences being:

• it splits the declaration and linkage of the function between the interface and implementation sections of the unit
• it uses an alias for the record type
• it uses aliases for Win32 data types

unit Winapi.Windows;

...

interface

...

type
  PSystemPowerStatus = ^TSystemPowerStatus;
  _SYSTEM_POWER_STATUS = record
    ACLineStatus : Byte;
    BatteryFlag : Byte;
    BatteryLifePercent : Byte;
    Reserved1 : Byte;
    BatteryLifeTime : DWORD;
    BatteryFullLifeTime : DWORD;
  end;
  {$EXTERNALSYM _SYSTEM_POWER_STATUS}
  TSystemPowerStatus = _SYSTEM_POWER_STATUS;
  SYSTEM_POWER_STATUS = _SYSTEM_POWER_STATUS;
  {$EXTERNALSYM SYSTEM_POWER_STATUS}

function GetSystemPowerStatus(var lpSystemPowerStatus: TSystemPowerStatus): BOOL; stdcall;
{$EXTERNALSYM GetSystemPowerStatus}

...

const
  ...
  kernel32  = 'kernel32.dll';
  ...

...

implementation

...
function GetSystemPowerStatus; external kernel32 name 'GetSystemPowerStatus';
...

end.