C / C++ / MFC

KarstenK18-Mar-10 22:15

KarstenK

18-Mar-10 22:15

"use XYZ in a efficient way" Blush | :O

Press F1 for help or google it.
Greetings from Germany

normanS9-Mar-10 22:37

normanS

9-Mar-10 22:37

Read up on unions and structures - that's the elegant way to do it.

Bitwise-and and right-shifting (suggested by the previous poster) will also do the job nicely.

«_Superman_»9-Mar-10 22:56

9-Mar-10 22:56

field1 = (data & 0x0F);
field2 = (data & 0x10) >> 4;
field3 = (data & 0xE0) >> 5;

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Mohan Ramachandra9-Mar-10 23:09

Mohan Ramachandra

9-Mar-10 23:09

A bit more optimization in field3

«_Superman_» wrote:
field3 = (data & 0xE0) >> 5;

field3 = data>> 5;

«_Superman_»9-Mar-10 23:21

9-Mar-10 23:21

Perfect.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

CPallini9-Mar-10 23:18

CPallini

9-Mar-10 23:18

The two different ways (you may find they are translated to the same asm, by the compiler).
[update] the first method's asm (SHIFT and AND operator) looks slightly faster)[/update]

struct BitField
{
  unsigned int f1:4;
  unsigned int f2:1;
  unsigned int f3:3;
};

union MyData
{
  unsigned char data;
  BitField bf;
};

int main(int argc, char *argv[])
{
  unsigned char data= rand();


  int field1, field2, field3;

  // using SHIFT and AND operators
  field1 =  data & 0xF;
  field2 = (data >> 4) & 1;
  field3 = data >> 5;

  printf("data=%d\n", data);
  printf("(1) fields: %d, %d, %d\n", field1, field2, field3);

  // using union and bitfield struct
  MyData md;
  md.data = data;

  field1 = md.bf.f1;
  field2 = md.bf.f2;
  field3 = md.bf.f3;
  printf("(2) fields: %d, %d, %d\n", field1, field2, field3);
  return 0;
}

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

modified on Wednesday, March 10, 2010 5:31 AM

KarstenK10-Mar-10 4:15

KarstenK

10-Mar-10 4:15

field 1.... bit 0-3 = > (data & 3)

and so on

Press F1 for help or google it.
Greetings from Germany

Dialog Box Resize [modified]

CPallini10-Mar-10 11:24

CPallini

10-Mar-10 11:24

KarstenK wrote:
field 1.... bit 0-3 = > (data & 3)

field 1.... bit 0-3 = > (data & 15)

FFY.
Smile | :)

shiv@nand9-Mar-10 21:48

shiv@nand

9-Mar-10 21:48

I have created 3 modeless child dialogbox dynamically on Parent dialog,

CDialogBoxDlg *m_Sel[3];

for(int i=0;i<3;i++)
{
m_Sel[i]=new CDialogBoxDlg();
m_Sel[i]->Create (IDD_DIALOG,this);
m_Sel[i]->ShowWindow (SW_SHOW);
}
after creating ,if i click on title bar and move the dialog1 or dialog2 or dialog 3,then it will not look clearly,if i Resize the Border then it will looks clearly.

i tried Invalidate(), UpdateWindow() and RedrawWindow() then also it is not working please help.

-- Modified Wednesday, March 10, 2010 4:12 AM

Re: Dialog Box Resize

Mohan Ramachandra9-Mar-10 21:53

Mohan Ramachandra

9-Mar-10 21:53

Did you call UpdateWindow in this way

for(int i=0;i<3;i++)
	{
		m_Sel[i]=new   CDialogBoxDlg();
		m_Sel[i]->Create (IDD_DIALOG,this);
		m_Sel[i]->ShowWindow (SW_SHOW);
		m_Sel[i]->UpdateWindow();
	}

modified on Wednesday, March 10, 2010 3:59 AM

Re: Dialog Box Resize

«_Superman_»9-Mar-10 22:10

Problem with WaitForSingleObject for multiple calls to ReleaseSemaphore

9-Mar-10 22:10

Also, you need to have an array of 3 locations - CDialogBoxDlg *m_Sel[3];
The valid locations are now from 0 to 2

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

temp.cyberfiles9-Mar-10 21:34

temp.cyberfiles

9-Mar-10 21:34

I am creating a blocking API implementation. For that i am using a semaphore which is initialized once in the beginning of the program. A pseudo code of the scenario is given below:

startProgram()
{
initCount = 0; //first call shall wait
semVariable = CreateSemaphore (NULL, initCount, 1, NULL);
}

I am calling the semaphore in my API:

API_my_blocking_func()//thread1
{
//Wait until data is ready in do_unblock()
if(WAIT_TIMEOUT == WaitForSingleObject (semVariable, timeout)
{
return WAIT_TIMEOUT ;
}

continues........

}

meanwhile in another thread, when data is ready, I am releasing semaphore so that API_my_blocking_func() continues.

do_unblock() //trhead2
{
if(data is ready)
ReleaseSemaphore (semVariable, 1, NULL);
}

----

Now I am having a problem : If ReleaseSemaphore (with semVariable) is called two times due to some reason,
the WaitForSingleObject is not waiting!

To my expectation, since the maximum count is set to 1 , releasing the semaphore
shall not increment semVariable above 1, whatever be the number of calls to ReleaseSemaphore . So the very next
WaitForSingleObject shall block.

How to achieve multiple release of semaphore is allowed, and a single WaitForSingleObject on the same semaphore shall block?

Re: Problem with WaitForSingleObject for multiple calls to ReleaseSemaphore

Cool_Dev9-Mar-10 22:09

Cool_Dev

9-Mar-10 22:09

its not clear what do you need. whenever the semaphore is released its count is increased and a WaitForSingleObject() will be unblocked. If you need to wait till a set of flags are signaled, use array of events or mutexes and use WaitForMultipleObjects()

Re: Problem with WaitForSingleObject for multiple calls to ReleaseSemaphore

temp.cyberfiles9-Mar-10 22:26

temp.cyberfiles

9-Mar-10 22:26

Since 'maximum count is set to 1' during semaphore initialization, when semaphore is released its count is increased to 1 only. Not beyond (is this true?). So n number of releases shall keep maximum count 1. And next wait shall decrement by 1 and thus block.

What I observed is : If i release same semaphore multiple times, I cannot wait on that semaphore in a single wait call.

Re: Problem with WaitForSingleObject for multiple calls to ReleaseSemaphore

Cool_Dev9-Mar-10 22:29

Cool_Dev

9-Mar-10 22:29

yea.. true.

How to register an ActiveX ocx file

rahul.kulshreshtha9-Mar-10 20:16

9-Mar-10 20:16

Hello All,

I am registering an ActiveX as follows:

CString ocxFile = L" /s \"" + ocxFile + L"\""; // for silent install
HINSTANCE hInstance = ::ShellExecute(NULL, L"open", L"regsvr32.exe", ocxFile, NULL, SW_HIDE);

It works fine when user has admin rights . If user does not have admin rights then it can not register. Any solution of it ?
I am developing in XP and testing in xp and win7

Thanks,
Rahul

«_Superman_»9-Mar-10 20:24

9-Mar-10 20:24

Registering an OCX is actually creating a few registry entries.
This requires admin rights by default unless the permission for the registry keys have been changed.
This is a good security feature.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

rahul.kulshreshtha9-Mar-10 20:26

9-Mar-10 20:26

Any way to give those permissions like showing UAC which will ask for an admin password.
If UAC is the solution then how to show UAC ?

Thanks,
Rahul

Rajesh R Subramanian9-Mar-10 20:28

Rajesh R Subramanian

9-Mar-10 20:28

Take a look at the link I've provided to you in my other post. You need to specify this in the manifest file.

“Follow your bliss.” – Joseph Campbell

rahul.kulshreshtha9-Mar-10 20:29

9-Mar-10 20:29

Thanks Rajesh!
I am looking into it.

«_Superman_»9-Mar-10 20:28

9-Mar-10 20:28

Go to Project Properties -> Configuration Properties -> Linker -> Manifest File.
Change UAC Execution Level entry to requireAdministrator.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

rahul.kulshreshtha9-Mar-10 21:05

9-Mar-10 21:05

Thanks Superman & Rajesh,

It worked but my applicaiton stores some data in applicationData folder.
So if I use UAC then it uses applicaitonData folder of administrator account.

There should be some way to use it's own application folder.

I want this because my application is user specific so I use application data folder as a storage place. But by using UAC normal user's data is getting store inside administrators application data.

To retrieve application data folder I am using

SHGetSpecialFolderPath(0, strPath, CSIDL_APPDATA, FALSE);

which is giving admin's aplication data folder after using UAC.

rahul.kulshreshtha9-Mar-10 21:22