Getting Windows Sleep message, works for some computers but doesn't work for others.

[c0d3r 17]

HI,  All

 

I'm getting a strange issue, the following codes were trying logout users when Windows is going to sleep mode. For some reason,  it works for some laptops, but it doesn't work for others:

 

procedure WMPowerBroadCast(var Msg: TMessage); message WM_POWERBROADCAST;

 

procedure TMainForm.WMPowerBroadCast(var Msg: TMessage);
begin
  if (Msg.wParam = PBT_APMSUSPEND) or (Msg.wParam = PBT_APMSTANDBY) then
  begin
    try
      Signout;
    except
    end;
    Msg.Result := 1;
  end;
end;

 

Got the report from my client,  the signout routine didn't get called when some laptops went to sleep (leave them opened and auto entered Sleep mode or Hitting Power button to force sleeping),  but other laptops/PCs were working just fine.

 

Edited April 20, 2023 by c0d3r

[programmerdelphi2k 237]

if many works, and 1 dont, my bet is: verify the setup BIOS, verify if same Windows edition or setup, etc...

[Angus Robertson 574]

Check the WM_POWER message as well.

 

Angus

 

[programmerdelphi2k 237]

my tests if SHUTDOWN

 

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    BtnDisplayTurnOFF: TButton;
    procedure BtnDisplayTurnOFFClick(Sender: TObject);
  private
    { Private declarations }
  public
    // WM_QUERYENDSESSION  when MSWindows start the "shutdown" or "restart"...
    procedure MyWMPowerBroadcastMessage(var AMessage: TMessage); message WM_POWERBROADCAST;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

const
  MY_MONITOR_OFF = 2;

  { TForm1 }

procedure TForm1.BtnDisplayTurnOFFClick(Sender: TObject);
begin
  SendMessage(Application.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, MY_MONITOR_OFF);
end;

procedure TForm1.MyWMPowerBroadcastMessage(var AMessage: TMessage);
begin
  case AMessage.WParam of
    PBT_APMQUERYSUSPEND:
      Memo1.Lines.Add('pc was PBT_APMQUERYSUSPEND at ' + DateTimeToStr(now));
    PBT_APMQUERYSTANDBY:
      Memo1.Lines.Add('pc was PBT_APMQUERYSTANDBY at ' + DateTimeToStr(now));
    PBT_APMQUERYSUSPENDFAILED:
      Memo1.Lines.Add('pc was PBT_APMQUERYSUSPENDFAILED at ' + DateTimeToStr(now));
    PBT_APMQUERYSTANDBYFAILED:
      Memo1.Lines.Add('pc was PBT_APMQUERYSTANDBYFAILED at ' + DateTimeToStr(now));
    PBT_APMSUSPEND:
      Memo1.Lines.Add('pc was PBT_APMSUSPEND at ' + DateTimeToStr(now));
    PBT_APMSTANDBY:
      Memo1.Lines.Add('pc was PBT_APMSTANDBY at ' + DateTimeToStr(now));
    PBT_APMRESUMECRITICAL:
      Memo1.Lines.Add('pc was PBT_APMRESUMECRITICAL at ' + DateTimeToStr(now));
    PBT_APMRESUMESUSPEND:
      Memo1.Lines.Add('pc was PBT_APMRESUMESUSPEND at ' + DateTimeToStr(now));
    PBT_APMRESUMESTANDBY:
      Memo1.Lines.Add('pc was PBT_APMRESUMESTANDBY at ' + DateTimeToStr(now));
    // PBTF_APMRESUMEFROMFAILURE: = PBT_APMQUERYSTANDBY
    // Memo1.Lines.Add('pc was PBTF_APMRESUMEFROMFAILURE at ' + DateTimeToStr(now));
    PBT_APMBATTERYLOW:
      Memo1.Lines.Add('pc was PBT_APMBATTERYLOW at ' + DateTimeToStr(now));
    PBT_APMPOWERSTATUSCHANGE:
      Memo1.Lines.Add('pc was PBT_APMPOWERSTATUSCHANGE at ' + DateTimeToStr(now));
    PBT_APMOEMEVENT:
      Memo1.Lines.Add('pc was PBT_APMOEMEVENT at ' + DateTimeToStr(now));
    PBT_APMRESUMEAUTOMATIC:
      Memo1.Lines.Add('pc was PBT_APMRESUMEAUTOMATIC at ' + DateTimeToStr(now));
    PBT_POWERSETTINGCHANGE:
      Memo1.Lines.Add('pc was PBT_POWERSETTINGCHANGE at ' + DateTimeToStr(now));
  else
    // you're going to want to handle PBT_APMRESUMECRITICAL (XP and older systems) and PBT_APMRESUMEAUTOMATIC differently
    // IIRC you did not get notification of the suspend in this case
    Memo1.Lines.Add('pc was <<OTHER NON-REPORTED>> at ' + DateTimeToStr(now));
  end;
end;

end.

 

[c0d3r 17]

16 minutes ago, Angus Robertson said:

Check the WM_POWER message as well.

 

Angus

 

The WM_POWER message is obsolete. It is provided only for compatibility with 16-bit Windows-based applications. Applications should use the WM_POWERBROADCAST message.

[c0d3r 17]

22 minutes ago, programmerdelphi2k said:

if many works, and 1 dont, my bet is: verify the setup BIOS, verify if same Windows edition or setup, etc...

Works for some, won't work for others (not only 1), and they are on Windows 10

[c0d3r 17]

32 minutes ago, programmerdelphi2k said:

my bet is: verify the setup BIOS

What should I look into?

[programmerdelphi2k 237]

maybe "State code" in hybernation options, compare with others... im not specialist in hardware, sorry!

[Angus Robertson 574]

Quote

Applications should use the WM_POWERBROADCAST message.

The important word there is 'should', many Windows APIs are considered historic and obsolete but are widely used and supported.

 

Angus

[programmerdelphi2k 237]

 

[Remy Lebeau 1393]

7 hours ago, c0d3r said:

I'm getting a strange issue, the following codes were trying logout users when Windows is going to sleep mode. For some reason,  it works for some laptops, but it doesn't work for others

On Vista+, you can use RegisterPowerSettingNotification() to register to receive WM_POWERBROADCAST notifications for certain power events.

 

On Windows 8+, you can use PowerRegisterSuspendResumeNotification() to receive power notifications via a callback function instead of WM_POWERBROADCAST.

 

IIRC, however, modern Windows also has a newer fast standby/hibernation mode that doesn't sent power notifications to applications, it just pauses and resumes them as if nothing had happened.  I can't find the details about that, but I remember being involved in past discussions about it, I just don't remember where.

[c0d3r 17]

23 hours ago, Remy Lebeau said:

On Vista+, you can use RegisterPowerSettingNotification() to register to receive WM_POWERBROADCAST notifications for certain power events.

 

On Windows 8+, you can use PowerRegisterSuspendResumeNotification() to receive power notifications via a callback function instead of WM_POWERBROADCAST.

 

IIRC, however, modern Windows also has a newer fast standby/hibernation mode that doesn't sent power notifications to applications, it just pauses and resumes them as if nothing had happened.  I can't find the details about that, but I remember being involved in past discussions about it, I just don't remember where.

Something must be changed, was told it was working just fine on the same computer, and then stop working.  They are using Windows 10.

Edited April 22, 2023 by c0d3r