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You will need to look at application wide hooking. That is, every time someone hit a key it gets preprocessed by your hook. A good place to start looking for this information is articles on custom menues, which offten need to hook the application inorder to change the appearance of all menues in the application. There are also, more than one article in the MSDN library on hooking (most are for subclassing though).
Keywords: hook, hooking, subclass, subclassing, application, system.
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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Hi,
I have a stylus (pen) whose coordinates are different from mouse coordinates. I tried to differentiate
the ratios but the stylus coordinates differ by mouse in speed , position and time. I thought of mouse hooking.
Like OnmouseMove() i have stylus OnMove() (sdk) , i thought if i could send the points generated by stylus in
OnMove() to the mouse callback function it should work,and i tried it i get assertions. Is there any way i could
map this stylus to mouse.
Thanx in advance.
ragiz
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What does speed have to do with it?
It all has to do with coordinates, which may have to be translated from one coordinate system to anouther. (Sounds like a math problem!)
What mouse callback function? (Not OnMouseMove())
Ok! In order for someone to answer your question.
1) What is the difference between the stylus and mouse coordinates?
2) What do you mean by "differ by mouse in speed, position and time"? (This is not physics!)
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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What does speed have to do with it?
The stylus which i have( uses laser )generates lots of coordinates when written slowly. if u keep the pen still it generates alot of points while mouse generates only one point.
What mouse callback function? (Not onmousemove())
is the mouse hooking ( WH_JOURNALPLAYBACK )which plays the mouse move which was recorded earlier.
Just tell me is it possible to map these two by any means.
Thanx for reply
rajiz
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I've did a little reading, this time>
Both WH_JOURNALPLAYBACK and WH_JOURNALRECORD are global for record and play back, they are probably not of much use for you purposes.
The MouseProc is application-defined, but it is only called after a mouse message is generated, and again does not seem to be what you need.
You may be able to have the DLL send mouse messages directly to your application, based on the stylus position.
If the resolution of the stylus is higher than the mouse resolution (which it sounds like it is), then you will have to calculate the relitive screen position from the given stylus position. If the relitive screen position changes: 1) save the position as current position and 2) Post (recommended) a mouse message to the application. You should only need to post a new message if the relitive mounse position changes; that is if the new calculated pixel position does not equal current position.
There should be some articles on posting mouse messages, some where.
I do not know if any of that helps, but my times up.
Good Luck!
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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i want to test how to change icon of an exe file with an icon file by function Updateresource() - do you know where i can find sample of this kind?
thx
includeh10
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This question is to general. It sounds like you are talking about changing an existing exe. It might be difficult to figure out how to change the icon resource of an existing file, but once known it should be easy provide the replacement and origanal are the same size.
Interesting: But, don't know how.
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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Try here[^].
Software Zen: delete this;
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Hi,
I have done a project and it was working fine all these days. Finally I had to add one more function so I created a new toolbar and attached the function to it,but when I run, this new toolbar button is not showing up. I also added this item in the menu bar....after running it is not showing up....any idea why is it acting like this??? Please do help, i have a deadline. I am sure it is nothing to do with the project, so I was thinking is this something to do with the system files of vc++.
Thanks a lot
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ashsri wrote:
I am sure it is nothing to do with the project, so I was thinking is this something to do with the system files of vc++.
Wrong!
I've been there too many times, always look at the project (source files) first.
(MFC 6.0 has a few minor (ligitimate) memory leaks).
-----------------------------------------------------------------------------
You can not attach a message function to a toolbar. A message function is
associated with a message, nothing more.
-----------------------------------------------------------------------------
What do you mean you created a new toolbar?
If that is actualy what you did, then you have to write code to switch to the new toolbar (or it will not show up), so you can use it.
Now I get the impression that you wanted to but did not add it to the existing toolbar.
Question: Did you create a new menu-bar the same way you created a new toolbar?
If you did, then you have the same problem in both places.
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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Hi,
I mean, I added few more items on the menu and the toolbar, to the one already existing. but it is not showing up when I run. I need not add any code, as I have already done it. So what I did was, just add or more items for the menubar and toolbar,and it is not showing up...thanks a lot for the help you are doing.
thanks
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Hi all,
I'm using VS 6.0 to try and explicitly load a DLL. However no
matter what I've tried GetProcessAddress() always returns NULL.
LoadLibrary works fine (not NULL anyway). I've checked the exported
name from the DLL via 'depends.exe' and it's not mangled: it shows
the same name ("fnTestDLL").
I've googled for a couple of hours with no luck, so I'm
out of ideas. Maybe it's my project settings? I've tried
including the testdll.lib in "Link", the testdll.h in testp.app
and the DLL in "Debug" all with no luck.
I've dumbed-down my code to the basics and still can't get it
to work. 
Any help would be greatly appreciated!!
------------------------------------------------------------
This is my App's "testapp.cpp" that (tries to) call my DLL:
------------------------------------------------------------
#include "stdafx.h"
#include "testapp.h"
#ifdef _DEBUG_
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
CWinApp theApp;
using namespace std;
typedef int (CALLBACK* LPFNDLLFUNC1)();
int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
{ .............. }
LPFNDLLFUNC1 LibMainEntryPoint;
HINSTANCE LoadMe = LoadLibrary("c:\\code\\begin\\testdll\\debug\\testdll.dll");
if (LoadMe == NULL)
{ ............. }
LibMainEntryPoint = (LPFNDLLFUNC1) GetProcAddress(LoadMe, "fnTestDLL");
if (LibMainEntryPoint == NULL)
{ ....ALWAYS FAILS HERE!!!...........}
LibMainEntryPoint();
FreeLibrary(LoadMe);
return (0);
}
----------------------------------------
This is my DLL's "testdll.cpp":
----------------------------------------
#include "stdafx.h"
#include "testdll.h"
using namespace std;
BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason, LPVOID lpreserved)
{
switch (ul_reason):
{
default: break;
}
return (TRUE);
}
TESTDLL_API int nTestDLL = 0;
TESTDLL_API int fnTestDLL(void)
{
return (42);
}
CTestDLL::CTestDLL()
{
cerr << "constructed";
}
CTestDLL::~CTestDLL()
{
cerr << "destructed";
}
-----------------------------------------------------
This is the DLL's "testdll.h":
-----------------------------------------------------
#ifdef TESTDLL_EXPORTS
#define TESTDLL_API __declspec(dllexport)
#else
#define TESTDLL_API __declspec(dllimport)
#endif
class TESTDLL_API CTestDLL
{
public: CTestDLL(void);
~CTestDLL(void);
};
extern TESTDLL_API int nTestDLL;
TESTDLL_API int fnTestDLL(void);
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'Depends' has a 'C++' button in the toolbar. Make sure it's not pressed. A sure sign that the name is in fact mangled is if the full signature appears in the list, i.e. int fnTestDLL(void).
Since you haven't wrapped the testdll.h contents with an extern "C" block, I suspect that the names are in fact mangled. You can perform an additional check using dumpbin /exports, which doesn't perform any translation.
You can fix this either by prefixing the 'flat' exports with extern "C", or by using a module-definition file[^]. The latter is useful if you want to define a different external name from the name in the code, or if you want to specify the ordinal.
Stability. What an interesting concept. -- Chris Maunder
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Thanks for the quick response. I don't see the C++ button you're talking about, but I'm using "Dependency Walker" version 1.0. It reports the name "?fnTestDLL@@YAHXZ" with entry point 0x00001082, which looks relatively correct to me, but I'm somewhat new to Windows DLLs, so maybe it IS mangled?
I'd prefer to stay away from EXP files if possible, simply because it should work without them.
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The "?fnTestDLL@@YAHXZ" is the mangled name. The "@@YAHXZ" is the 'mangled' portion, and identifies the argument signature for the function.
Software Zen: delete this;
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GetProcAddress(LoadMe, "fnTestDLL") fails becuase "fnTestDLL" does not exist in the DLL. [ GetLastError() ] No I am not kidding. If it failed the it is probably correct, so dig deeper.
Curriosity:
TESTDLL_API int nTestDLL = 0; // What is this for ( no given code uses it)
TESTDLL_API int fnTestDLL(void)
{
return(42);
}
INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen
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Thanks all!! By using the (ugly) name of "?fnTestDLL@@YAHXZ" instead of "fnTestDLL" it works fine. I think there are ways to export nicer sounding names for users of the DLL, which I'll have to look into, but at least now I can call this DLL. I can even create an instance of type CTestDLL now! (exported the public methods of the class, not the whole class, since apparently you can't export private class members/methods outside a DLL and exporting the whole class causes problems) Although the destructor doesn't seem to get called which is weird, but I'll read-up on that.
John> I included the "nTestDLL" because I'm trying to learn how to call DLLs, so I wanted to know how to export variables and not just functions. You're correct, my testapp doesn't currently use that variable at all.
Thanks again all for the help.
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What is the include needed for graphics that is equivilent to the "#include <graphics.h>" in the Bordland Version of C++. Any help is appreciated.
Thanks,
Jon
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There is no such thing in visual c. The graphics routines you are talking about are borland specific and are just an extension on code that borland wrote for Turbo Pascal about 20 years ago.
John
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If we are talking windows programming than the basic drawing functions (GDI functions) are included when you include the windows header file (windows.h). For console based applications if you look at www.cprogramming.com some people have written custom graphics functions for use with console based apps. Just due a search from the main page.
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With a MFC application I need to run a routine every 40msec.
Currently I am using the Standard Win32 Timers;
e,g, SetTimer(TIMER1, 40);
But sometimes it fires late.
I have the option to use an interrupt from a 3rd party PCI card. But as only 1 interrupt, could I use NAMED EVENTS to time actions on other applications, again with a resolution of ~ 40 msec.
e.g. Other applications with worker threads waiting for the EVENT to be fired via the interrupt routine.
Do you this will work on a PC 1.7 GHz processor, clock res = 1msec; with Windows 2000?
grahamfff
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Hello !
Windows is not the best platform for time-critical applications. If you must use it, though, you could try increasing the priority of your application to maximum level. This ensures that the 40 ms (I assume milliseconds, here)timer is fired as close to 40 ms intervals as possible.
Increasing the priority of your application will cause other applications to lose theirs: increasing the accuracy of your application might/will cause inaccuracy/stiff response/high latency in other applications concurrently executing in the system. Pushing one application to real-time priority will most likely cause the operating system to appear 'locked up' while this single application is executing. The timer will reach as close to 40 ms intervals as possible, though. That's the price you'll have to pay.
When designing the real-time thread, you must make it as low-resource hog as possible.
For an example, create a thread, increase it's priority and call SetTimer Win32 API routine with a pointer to the function that should run at 40 ms intervals. Then put this thread into a forever loop that can be interrupted, if necessary. When interrupted, the timer should be killed and the thread terminated. Note that this will not cause the system to lock up, because the priority of the process itself has not been raised. You could use SetPriorityClass to pump up the process priority as well. Before doing this, familiarize yourself with Scheduling Priorities[^] in the MSDN or in Visual Studio documentation. Misusing thread or process priorities is a sure way to get your computer locked up easily.
To set max priority for your MFC application's main thread, use AfxGetApp() to get the CWinApp object pointer, and call CWinThread::SetThreadPriority() with a parameter THREAD_PRIORITY_TIME_CRITICAL through this pointer. CWinApp derives from CWinThread. MFC does not have a direct routine to pump up process priority. You'd need to use a mixed-mode call (CWinThread::operator HANDLE and SetPriorityClass) to accomplish this.
A precisely 40 ms timer with not a single micro-second delay or advance is impossible in a modern operating system. For such a purpose, you'd need to design and implement a micro-controller or similar solution.
Named events are used to schedule interprocess actions, or interthread actions. For example, you could create an event object in a remote thread to mark when this thread has ran a single loop. When the event object is signaled, a loop is complete and the next loop is starting, if it's a continous system. Event objects can be global or local, determining how they are created. Global of interprocess, local for interthread should be your general rule.
Even if you used named events, you would need some method to set the event to a signaled state whenever 40 ms has passed. This will again lead you back to the timing issue and the timers. Named events is the easiest way to signal other threads or processes that your 40 ms interval has passed, though.
Hope this helps.
-Antti Keskinen
----------------------------------------------
The definition of impossible is strictly dependant
on what we think is possible.
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Timer (WM_TIMER) messages have the very lowest priority in Windows. Even paint messages have a higher priority than timer messages. You shouldn't expect reliable behaviour from these timers.
Windows offers two other timer facilities: multimedia timers and waitable timers. For the first see Using Multimedia Timers[^]. For the second see the CreateWaitableTimer[^] function.
Another alternative is to decide whether you really need that resolution. If you're simply trying to update a timer display, measure the actual elapsed time using GetTickCount.
It sounds like you're trying to write a real-time system. Windows 2000 is not a real-time OS - the interrupt latencies are simply not predictable. If this is what you're trying to do, either obtain a real-time kernel which runs Windows as a subtask, or use Windows CE.
Stability. What an interesting concept. -- Chris Maunder
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