C / C++ / MFC

Re: Knowing if a window is going to be visible at creation

8-Aug-06 6:12

Did you look at the CREATESTRUCT in the LPARAM of the message?

led mike

Kharfax8-Aug-06 6:57

Re: Knowing if a window is going to be visible at creation

8-Aug-06 6:57

Yeap, im testing it like this

if(pCreateStruct->style & WS_VISIBLE == WS_VISIBLE)

and always is false Frown | :(

led mike8-Aug-06 10:31

Re: Knowing if a window is going to be visible at creation

8-Aug-06 10:31

if((pCreateStruct->style & WS_VISIBLE) == WS_VISIBLE)

led mike

Kharfax8-Aug-06 11:02

Re: Knowing if a window is going to be visible at creation

8-Aug-06 11:02

If I use

if((pCreateStruct->style & WS_VISIBLE) != WS_VISIBLE)

(notice the != )

it works, another computer science mystery.

Thanks a lot for the tips mate Big Grin | :-D

led mike8-Aug-06 11:26

Re: Knowing if a window is going to be visible at creation [modified]

8-Aug-06 11:26

Kharfax wrote:
it works

Well if I follow the entire thread correctly it is not what you want since you are now testing that the WS_VISIBLE style is NOT set!

Consider this possible window creation sequence:

A) application code calls CreateWindow passing a style.... say WS_POPUP
B) OS sends a WM_CREATE containing the style
C) your hook recieves this message and the style WS_VISIBLE is not set
D) application code handles the WM_CREATE message and changes the window style to WS_VISIBLE

led mike

Kharfax9-Aug-06 2:14

Re: Knowing if a window is going to be visible at creation

9-Aug-06 2:14

Damn, now it works because it shows all Big Grin | :-D

Kharfax9-Aug-06 3:06

Re: Knowing if a window is going to be visible at creation

9-Aug-06 3:06

I need to get only the applications that appear in the task administrator.
The filter only shows user apps with a visible window.

Im trying to do the same kind of filtering.

but it seems that WS_VISIBLE is troublesome...
Maybe I can check another style, and get the same results..

I dont know, for example, WS_SYSMENU or WS_CAPTION, the only problem I see is with skinned apps that have a simulated SYSMENU :S

What do you think about this approach?

led mike9-Aug-06 5:38

Re: Knowing if a window is going to be visible at creation

9-Aug-06 5:38

Kharfax wrote:
What do you think about this approach?

At this point I am not convinced that I have a complete understanding of the requirements.

Kharfax wrote:
I need to get only the applications that appear in the task administrator.

I guess you refer to the "Windows Task Manager" and the list of processes in the "Applications" tab?

If so there is a completely different way to accomplish that rather than using a System hook. There are APIs that allow you to get the list of running processes.

I would think some Google would find articles and sample code to get you much of the way there. There might even be a Code Project Article. The MSDN Documentation[^] on Process Enumeration is a good place to start if you want to figure it out for yourself.

One example approach might be using the GetStartupInfo() API that returns a STARTUPINFO structure. The structure has a member for which the documentation states:

lpTitle
    For console processes, this is the title displayed in the title bar if a new console 
window is created. If NULL, the name of the executable file is used as the window title 
instead. This parameter must be NULL for GUI or console processes that do not create a 
new console window.
dwX

led mike

Kharfax9-Aug-06 5:59

Re: Knowing if a window is going to be visible at creation

9-Aug-06 5:59

I will check that approach using GetStartupinfo

I have the hook, to know among other things, when a new window is created by a user.
The hook is used for my "single sign on" app, thats why i'm using it.
If that window belongs to an App like the one in task manager "applications" tab
I need to report the opening to a local service.

The problem is for example with the calculator and other apps.

I get

exe: calc.exe
windows title: calcMsgPump

or some crap like that, that's why I want only the visible windows.

led mike9-Aug-06 12:12

Re: Knowing if a window is going to be visible at creation

9-Aug-06 12:12

Kharfax wrote:
or some crap like that

What is wrong with that?

Kharfax wrote:
that's why I want only the visible windows.

I don't understand, when you start the calculator it shows up in the "Task Manager - Applications" tab. So it "is" visible and therefore you want to find it, correct?

led mike

Kharfax10-Aug-06 2:23

Re: Knowing if a window is going to be visible at creation

10-Aug-06 2:23

Check the win title.

I get as if two windows open

calc.exe Title:Calculator <- This one is OK

calc.exe Title:CalcMsgPumpWnd <- I dont see this one either in Applications tab or my screen

I would like to obtain only the apps I see in Task Manager apps tab.

led mike10-Aug-06 4:41

10-Aug-06 4:41

ok that clears that up.

You might consider using the hook for WM_CREATE as just an event. Meaning that upon the event you use the process enumeration methods and process API's like GetStarupInfo() etc. to build your list.

led mike

Syntax problem

Jay038-Aug-06 5:25

Jay03

8-Aug-06 5:25

This syntax with all those brackets is scaring me....
Can someone please tell me what is going on?

for ( unsigned int j = 0; j < ms_numInstances; j++ )<br />
               {<br />
                  ( *( (Ball*)(ms_instances[j]) ) ).m_stateTimeInterval = timeInterval;<br />
               }

Thank You! Smile | :)

Kharfax8-Aug-06 5:37

8-Aug-06 5:37

Is casting whatever there is inside ms_instances array to a Ball object pointer, and then is refering to that object that is beign pointed, you can resume it like this:

Ball b;
b.m_stateTimeInterval = timeInterbal;

Obviously dont replace the code, is just for you to see the same in a more simpler way

Hope it helps

David Crow8-Aug-06 5:37

David Crow

8-Aug-06 5:37

It could also be written as:

for (...)
{
    Ball *pBall = ms_instances[j];
    ( *pBall ).m_stateTimeInterval = timeInterval;
    // or
    pBall->m_stateTimeInterval = timeInterval;
}

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Viorel.8-Aug-06 5:38

Viorel.

8-Aug-06 5:38

I would prefer this:

for ( unsigned int j = 0; j < ms_numInstances; j++ )
{
    Ball * const ball = ms_instances[j];
    ball->m_stateTimeInterval = timeInterval;
}

Now it seems much clearer, I think. The ms_instances array contains pointers to Ball objects. This loop initializes the m_stateTimeInterval field of all of Ball objects.

Jay038-Aug-06 6:33

Jay03

8-Aug-06 6:33

Viorel. wrote:
The ms_instances array contains pointers to Ball objects

What happens when j = 0;

Ball * const ball = ms_instance[0];

Does this mean it has no pointers because ms_instance[0] ?
Do you need atleast j = 1 to create a pointer ........ like ms_instance[1] means 1 pointer
.... ms_instance[2] means array of two pointers......... so what does 0 mean?

ball->m_stateTimeInterval = timeInterval;

--------------------------------------------------------------------------------------------

So for each j value, there will be an array of pointers created?

Zac Howland8-Aug-06 6:35

Zac Howland

8-Aug-06 6:35

Jay03 wrote:
Ball * const ball = ms_instance[0];

Arrays in C/C++ are 0-based. This line will access the first element in the ms_instance array and cast it to a pointer-to-a-Ball.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

C^hris L^osinger8-Aug-06 5:40

C^hris L^osinger

8-Aug-06 5:40

ms_instances is apparently an array of pointers to instances of some kind of object.

this code gets element 'j' (a pointer) out of the array, then casts that pointer to a pointer-to-a-Ball: "compiler, treat this pointer as if it was a pointer to a Ball, instead of a pointer to whatever it is actually pointing at. then it dereferences the pointer and sets the m_state* member variable of what we all hope is an actual Ball object.

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