Keep Windows awake

Keep-Windows-Awake.c

// Build: x86_64-w64-mingw32-gcc -Wall -mwindows -Os -s -o Keep-Windows-Awake.exe Keep-Windows-Awake.c

#include <windows.h>

int main() {
	/* Keep Windows awake for the lifetime of this thread */
	SetThreadExecutionState(ES_CONTINUOUS | ES_SYSTEM_REQUIRED);
	/* Wait via a messagebox */
	MessageBox(NULL, "Windows is now being prevented from falling asleep.\n\nPress OK to end this...", "Keep-Windows-Awake", MB_OK | MB_ICONINFORMATION);
}

UKeepAwake.pas

unit UKeepAwake;

interface

uses
  Windows;

type
  EXECUTION_STATE = DWORD;

const
  ES_SYSTEM_REQUIRED = $00000001;
  ES_DISPLAY_REQUIRED = $00000002;
  ES_USER_PRESENT = $00000004;
  ES_AWAYMODE_REQUIRED = $00000040;
  ES_CONTINUOUS = $80000000;

function SetThreadExecutionState(esFlags: EXECUTION_STATE): EXECUTION_STATE; stdcall; external kernel32;

procedure KeepAwake;

implementation

procedure KeepAwake;
begin
  SetThreadExecutionState(ES_SYSTEM_REQUIRED or ES_DISPLAY_REQUIRED);
end;

end.