hook the WM_PRINTCLIENT evenet - C / C++ / MFC Discussion Boards

Re: what kind of window can have a caret?

code_discuss8-Apr-08 0:46

code_discuss

8-Apr-08 0:46

Re: what kind of window can have a caret?

BadKarma8-Apr-08 1:15

BadKarma

8-Apr-08 1:15

Thats easy,

the CBugsBunnyWnd Poke tongue | ;-P

codito ergo sum

Re: what kind of window can have a caret?

Rajesh R Subramanian8-Apr-08 2:43

Rajesh R Subramanian

8-Apr-08 2:43

Isn't this kind of obvious? You'll have a caret only where there is a text-area (where you could possibly type and the letters appear). What possibly made you ask such a question?

Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP

Re: what kind of window can have a caret?

Michael Schubert8-Apr-08 4:21

Michael Schubert

8-Apr-08 4:21

I bet he can almost smell your angry gas... Poke tongue | ;-P

Re: what kind of window can have a caret?

Rajesh R Subramanian8-Apr-08 22:10

Rajesh R Subramanian

8-Apr-08 22:10

Probably yes. Laugh | :laugh:

Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP

Re: what kind of window can have a caret?

Mark Salsbery8-Apr-08 6:35

Mark Salsbery

8-Apr-08 6:35

You can use the caret in any window you want to.

Since a caret is generally used to mark an insertion point, it only really makes sense to use
it where the user can insert something.

Carets[^]

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: what kind of window can have a caret?

Hamid_RT10-Apr-08 6:51

Hamid_RT

10-Apr-08 6:51

Caret is for text and editbox is for enter the textes but I guess your intent is focus,right?

hook the WM_PRINTCLIENT evenet

micutzu8-Apr-08 0:02

micutzu

8-Apr-08 0:02

Hello,

Can anyone point me a smaple that shows me how to hook the WM_PRINTCLIENT event.

Thank you!

Re: hook the WM_PRINTCLIENT evenet

code_discuss8-Apr-08 0:08

code_discuss

8-Apr-08 0:08

http://www.fengyuan.com/article/wmprint.html[^]

and I strongly suggest you buy his book.

Re: hook the WM_PRINTCLIENT evenet

micutzu8-Apr-08 0:27

micutzu

8-Apr-08 0:27

Thank you!

Can you tell me (I am not sure) if this event WM_PRINTCLIENT is related with the user pressing Print button?

I want to make sure that I get this event when the user want to print a page.

System Shutdwon

john56327-Apr-08 23:58

john5632

7-Apr-08 23:58

Hi,
Follwoing code is not working for shutting down a system.

if(ExitWindowsEx(EWX_REBOOT|EWX_FORCE,0))
AfxMessageBox(_T("Restart"));
else
{
if(InitiateSystemShutdownEx(NULL,NULL,NULL,FALSE,TRUE,NULL))
AfxMessageBox(_T("Restart1"));
}

Re: System Shutdwon

Rajesh R Subramanian8-Apr-08 3:43

Rajesh R Subramanian

8-Apr-08 3:43

Did you check the return value of ExitWindowsEx()?

See this secret link: How to shut down the system[^]

Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP

Re: System Shutdwon

David Crow8-Apr-08 3:58

David Crow

8-Apr-08 3:58

pther wrote:
Follwoing code is not working for shutting down a system.

Ok. So what's it doing?

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: System Shutdwon

Hamid_RT8-Apr-08 22:05

Hamid_RT

8-Apr-08 22:05

See http://www.codeproject.com/KB/system/StayON.aspx[^].

global and static object

George_George7-Apr-08 23:40

George_George

7-Apr-08 23:40

Hello everyone,

This is what mentioned in the book, ATL Internals about why Release function of CComPtr and CComQIPtr is needed for global and static variable.

--------------------
The destructor for global and static variable only executes after the main function exits, long after CoUninitialize runs, (That is, if it runs at all. You must link with the C++ runtime library for the constructors and destructors of global and static variable to run.) ATL itself doesn't use the C/C++ runtime library; thus, by default, ATL components don't link with the library.
--------------------

I do not quite understand what means "must link with the C++ runtime library for the constructors and destructors ... to run"? Could anyone help please?

thanks in advance,
George

Re: global and static object [modified]

Matthew Faithfull8-Apr-08 0:23

Matthew Faithfull

8-Apr-08 0:23

Try this experiment and you will see.
Find or write some code like this

<br />
<br />
//.h<br />
class CSomeclass<br />
{<br />
  public:<br />
  static int MyMember;<br />
};<br />
<br />
//.cpp<br />
//PLACE A BREAKPOINT ON THE LINE BELOW<br />
int CSomeclass::MyMember = 42;<br />
<br />

Place a breakpoint on the assignment and also one at the beggining of your code, in main or InitiInstance or whatever.
Run under Debug and you may be surprised at what happens. When the debugger stop take a look at the call stack and the order in which the breakpoints are hit. Smile | :)

Bootstrapping an MSVC C++ program is about 10,000x more complex than most people realize.

Nothing is exactly what it seems but everything with seems can be unpicked.

modified on Tuesday, April 8, 2008 6:40 AM

Re: global and static object

George_George8-Apr-08 4:21

George_George

8-Apr-08 4:21

Thanks Matthew,

To my surprise, when set a break point to the assignment line, when execute the program, the break point will automatically moved to the beginning of main. Any ideas?

//.h
class CSomeclass
{
public:
static int MyMember;
};

//.cpp
//PLACE A BREAKPOINT ON THE LINE BELOW
int CSomeclass::MyMember = 42;

int main()
{
	return 0;
}

regards,
George

Re: global and static object

Matthew Faithfull8-Apr-08 4:39

Matthew Faithfull

8-Apr-08 4:39

Hmm, not sure, are you linking to the C Runtime, MSVCRT.dll or that static lib equivalent. You can find out by looking at the value of CSomeclass::MyMember when main() gets called if it's not 42 then static initialization is not being called hence it's reasonable it won't let you set a breakpoint on a line that's never called. Try changing from a CONSOLE subsystem app to a WINDOWS subsystem app as well as that makes a differenece to the entry point used. You'll need a WinMain function to get a raw windows app off the ground without MFC. If you have a look in your equivalent of
C:\Program Files\Microsoft Visual Studio 8\VC\crt\src\crtexe.c
, assuming you installed it, you'll see the code that actually runs when you application starts up. The call to _initterm( __xc_a, __xc_z ) at around Line 512 is where your static class members like CSomeclass::MyMember.
Please don't ask me to explain it. It's 'for reference only'. Smile | :)

Nothing is exactly what it seems but everything with seems can be unpicked.

Re: global and static object

George_George8-Apr-08 22:10

George_George

8-Apr-08 22:10

Thanks Matthew,

I think C++ Runtime library is fundamental and ATL is also C++ code, I do not understand why ATL is not dependent on C++ Runtime library? What functions are provided by C++ Runtime library besides STL, which ATL is not dependent on?

regards,
George

Re: global and static object

Matthew Faithfull9-Apr-08 3:07

Matthew Faithfull

9-Apr-08 3:07

You could try using the depends.exe tool that comes with Visual Studio. Use it to open MSVCRT.dll and look at the lower of the 2 panes on the right hand half of the upper window.
This will list all the stuff MSVCRT exports, a lot of functions. Many of these are defined by the C Language standard which describes a set of library functions which are to be available with the language. You can probably find a copy of the standard on the internet somewhere. Some of the others are widely implemented extensions to the standard, others are Microsoft specific additions and a few are wierd undocumented stuff for supporting the underpinnings of Windows and even integrating with .NET. It's a beastly big library and although Microsoft do provide the source, due to code injection they don't actually provide quite all of it and it certainly isn't open. The main alternative C Library which has all the standard functions in it and more is glibc the GNU C Library which is what GNU-Linux uses and which runs just about everywhere except on Windows Frown | :(

It would be lovely if someone produced a fully open source completely standards compliant C Library compatible with MSVCRT and with glib and that runs absolutely everywhere , sadly that would take many, many person years of work.

Nothing is exactly what it seems but everything with seems can be unpicked.

Re: global and static object

George_George9-Apr-08 3:43

George_George

9-Apr-08 3:43

Thanks Matthew,

Suppose I have an ATL DLL, which is not dependent on CRT. And in the DLL, I implement a COM in-proc server. If I have another EXE, which will use the DLL COM server and the EXE is dependent on CRT.

Are there any chances the constructors of the global/static objects executed, e.g. when loaded by EXE before DllMain? And why?

regards,
George

Re: global and static object

Matthew Faithfull9-Apr-08 3:59

Matthew Faithfull

9-Apr-08 3:59

I'm not sure exactly what you're asking. If you have an ATL DLL which doesn't link, even implicitly, to the CRT but contains statics and non const globals then 1 of 2 things must be true.

1 ATL must provide a static initialization mechanism independent of the CRT. (As far as I know this is not true)

or

2 Your statics won't get initialized.

I would guess that in fact if you add statics and non const globals to an ATL DLL then it does become implicitly dependent on the CRT, even if there's no explicit linkage.
You could experiment with the /nodefaultlib option of the linker and specify exactly which libs you will and won't link to to see what effect that has. You can code breakpoints directly into any static initialization code you think may be being called before your debugger normally get involved using DebugBreak(); or even __asm{ int 3 }; a useful if naughty trick Wink | ;)

Watch out for implicitly linked Dlls that get loaded dynamically but right at startup and for Libs your project 'inherits' out of thin air. The $NOINHERIT linker options can be invaluable.
Obviously I wouldn't recommend doing any of this with any project you can't afford to break as break it you most ccertainly will if you banish the CRT. Smile | :)

Nothing is exactly what it seems but everything with seems can be unpicked.

Re: global and static object

George_George9-Apr-08 15:19

George_George

9-Apr-08 15:19

Thanks Matthew,

Matthew Faithfull wrote:
get involved using DebugBreak(); or even __asm{ int 3 };

Why I need to code explicitly DebugBreak? Why not can I just double click to set a break point to the line of constructor of global/static variable in VS? Smile | :)

regards,
George

Re: global and static object

Matthew Faithfull10-Apr-08 6:21

Matthew Faithfull

10-Apr-08 6:21

Believe it or not the VS Debugger is not perfect and sometimes it will miss breakpoints if they are too 'early' in the code. Either because it doesn't think the line will be called or because it isn't completely ready when that line is hit. Sometimes static construction can fall into this trap and become 'undebuggable' although not usually. It may also depend on whether the Debugger can find and match the source for the CRT.

Nothing is exactly what it seems but everything with seems can be unpicked.

Re: global and static object

George_George10-Apr-08 15:40

George_George

10-Apr-08 15:40

Thanks Matthew,

Where to set DebugBreak in the sample we discussed before? Confused. Smile | :)

//.h
class CSomeclass
{
public:
static int MyMember;
};

//.cpp
//PLACE A BREAKPOINT ON THE LINE BELOW
int CSomeclass::MyMember = 42;

int main()
{
	return 0;
}

regards,
George

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.