Window's Sleep mode
Chuck Savage
to trap it and keep Windows from entering a sleep state programaticaly?
This a quote from client:
"B. When I left the program running all night long, when I came back in the
next morning and "woke" the computer up by moving the mouse, the program
would not respond. This was also on the Windows XP system which went into
screensaver mode and then into a sleep mode."
Info on program operation:
My program uses a thread to capture signals from the serial port, and when
data arrives passes it to the main thread to be processed. I am thinking
that if Windows goes to sleep (and doesn't have serial port wakeup enabled)
that the information is buffered and/or lost; possibly freezing up the
application.
--
Charles Savage
Software Engineer
HWI Manufacturing
Remy Lebeau
"Chuck Savage" <csa...@hwimfg.com> wrote in message
news:3c630b69$1_2@dnews...
> What message is sent when Windows enters sleep mode?
WM_POWERBROADCAST. Test the wParam parameter for PBT_APMQUERYSUSPEND.
> Also, is there a way to trap it and keep Windows from entering a
> sleep state programaticaly?
Simply return BROADCAST_QUERY_DENY when handling the message.
Gambit
Chuck Savage
> Simply return BROADCAST_QUERY_DENY when handling the message.
I'm still learning the basics of Messages and sending them, etc.
I wrote this...
in header...
class TfrmMain : public TForm
{
__published: // IDE-managed Components
private: // User declarations
void __fastcall ProcessMessage(TMsg &message, bool &handled);
public: // User declarations
__fastcall TfrmMain(TComponent* Owner);
};
in .cpp
void __fastcall TfrmMain::ProcessMessage(TMsg &message, bool &handled)
{
switch( message.message )
{
case WM_POWERBROADCAST:
switch( message.wParam )
{
case PBT_APMQUERYSUSPEND:
handled = true;
break;
default:
handled = false;
break;
}
break;
case WM_SYSCOMMAND:
switch( message.wParam )
{
case SC_SCREENSAVE:
handled = true;
break;
default:
handled = false;
break;
}
break;
default:
handled = false;
break;
}
}
__fastcall TfrmMain::TfrmMain(TComponent* Owner)
: TForm(Owner)
{
Application->OnMessage = ProcessMessage;
}
Any help would be appreciated.
Remy Lebeau
to return your own values in response to messages. You need to intercept
the message on the form level instead, either 1) overriding WndProc() or 2)
using a MESSAGE_MAP
Gambit
"Chuck Savage" <csa...@hwimfg.com> wrote in message
news:3c64437b$1_1@dnews...
Chuck Savage
with all the different names? IE how would I look up as you gave me,
WM_POWERBROADCAST and the different wParam's that it has, such as the one
you gave me (PBT_APMQUERYSUSPEND).
Chuck Savage
books I'm reading show WndProc to be setup something like...
void __fastcall TfrmMain::WndProc(Messages::TMessage &Message)
{
// my code here
TForm::WndProc(Message);
}
Each example I see has WndProc as defined as returning void. And the
MessageMap's defined as returning void. For a refference I'm looking at
Borland C++ Builder 4 Unleashed, pgs 68 & 69. Plus the C++ Builder How-To
book pg 337.
(Reffering to my previous post) I've found the message definitions in
winuser.h, but is there a book that describes when to use what?
Bob Gonder
Remy Lebeau
Custom install, then you'll see the option to install the reference. Or you
can grab the files off of your Builder CD directly. Or you can do a search
at http://msdn.microsoft.com/search
Gambit
"Chuck Savage" <csa...@hwimfg.com> wrote in message
news:3c644a3a_2@dnews...
Remy Lebeau
> Each example I see has WndProc as defined as returning void. And the
> MessageMap's defined as returning void.
Correct. However, both WndProc() and MESSAGE_MAP handlers pass message
information in a TMessage-derived structure. Such structures have a Result
value that you can assign return values in.
In the case of the issue at hand, the code would look something like this:
// via WndProc()
void __fastcall TfrmMain::WndProc(TMessage &Message)
{
if(Message.Msg == WM_POWERBROADCAST)
{
if((Message.WParam == PBT_APMQUERYSUSPEND) &&
(!SomeConditionToAllowTheSuspend))
{
Message.Result = BROADCAST_QUERY_DENY;
return;
}
}
// pass the message to default processing
TForm::WndProc(Message);
}
// via MESSAGE_MAP
class TfrmMain : public TForm
{
private:
void __fastcall WMPowerBroadcast(TMessage &Message);
public:
BEGIN_MESSAGE_MAP
VCL_MESSAGE_HANDLER(WM_POWERBROADCAST, TMessage,
WMPowerBroadcast)
END_MESSAGE_MAP(TForm)
};
void __fastcall TfrmMain::WMPowerBroadcast(TMessage &Message)
{
if((Message.WParam == PBT_APMQUERYSUSPEND) &&
(!SomeConditionToAllowTheSuspend))
{
Message.Result = BROADCAST_QUERY_DENY;
return;
}
// pass the message to default processing
TForm::Dispatch(&Message);
}
Gambit
Chuck Savage
A dialog box pops up saying that the system cannot suspend becase a device
or program has prevented it. Close all applications and try again. Thing
is, this is a medical applicaiton that needs to be up and running at all
times. Anyway to disable that dialog box, because it takes control away
from the program. Clicking ok, would just reenable the timer that would
eventually re-popup the dialog box.
Remy Lebeau
Panel and go to Display), the go to the Screen Saver tab and click on the
"Settings" button in the EnergyStar section, are you running under the
"Always On" power scheme? Try playing around with those settings a little,
maybe you won't even need to deal with catching WM_POWERBROADCAST at all
then.
Gambit
"Chuck Savage" <csa...@hwimfg.com> wrote in message
news:3c682e77_2@dnews...
Chuck Savage
instructions. I wanted to try and keep it transparent to the enduser.
"Remy Lebeau" <gamb...@gte.net> wrote in message news:3c683f5d$1_1@dnews...
Remy Lebeau
I've never actually done anything with the power management stuff before, I
know just enough to get the notifications for it, not what happens
afterwards.
Perhaps the settings for the Power schemes are in the registry somewhere?
Not sure. But if they were, then you could try modifying the registry to
enable/disable it.
Gambit
"Chuck Savage" <csa...@hwimfg.com> wrote in message
news:3c684a06$1_1@dnews...