Re: Bit Shift and Mask - C / C++ / MFC Discussion Boards

Re: mouse cursor not shown in the CScrollView

Iain Clarke, Warrior Programmer23-Jul-09 9:03

23-Jul-09 9:03

For no cursor.... See if the CMyScrollView::PreCreate.... class sets its window class to have NULL as a cursor, and look at the OnSetCursor method.

Alternatively, does it try to load a cursor resource that doesn't exist anymore, fail poorly, and do (equiv) SetCursor (NULL)?

Iain.

I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need cotract work done, give me a job! http://cv.imcsoft.co.uk/[^]

Re: mouse cursor not shown in the CScrollView

transoft23-Jul-09 9:17

transoft

23-Jul-09 9:17

Hi Iain

I did not do anything related to cursor in the "CMyScrollView::PreCreateWindow"

I have no "OnSetCursor" method.

When I moved my cursor into View client area, cursor just despair.

Thanks,

Re: mouse cursor not shown in the CScrollView

Iain Clarke, Warrior Programmer23-Jul-09 9:26

Iain Clarke, Warrior Programmer

23-Jul-09 9:26

Do you do something with OnNcHitTest? Maybe you're returning something odd...

Iain.

Re: mouse cursor not shown in the CScrollView

transoft23-Jul-09 10:09

transoft

23-Jul-09 10:09

No, I have not defined "OnNcHitTest" method yet.

Thanks,

Using vista's virtualisation

Kees195823-Jul-09 7:25

Kees1958

23-Jul-09 7:25

Hello,

I am not a programmer but I need a simple program (assembled C++ code) for the following

Start ProcessX
Set TokenVirtualizationEnabled using SetTokenInformation for processX

Ideally the name of process X (or exact location directory) should be passed over through a parameter. like

this_is_what_I_need.exe /C:\Windows\Programs\Example\processX.exe

or

this_is_what_I_need.exe ProcessX.exe

Thanks in advance

Bit Shift and Mask

resolvequestion23-Jul-09 6:29

resolvequestion

23-Jul-09 6:29

I have data coming in and I store the one byte header in the struct

struct {
unsigned char flags;
unsigned char Checksum;
unsigned short int Sequence;
} PAcket Header

Now I need to read individually First, second, third & fourth bit and than need to read remaining 4 bits from the "flag" byte.

How do I do this. plz help....
THANKS!

Re: Bit Shift and Mask

Cedric Moonen23-Jul-09 7:40

Cedric Moonen

23-Jul-09 7:40

This article[^] should help you getting the basics with bit masking.

Cédric Moonen
Software developer

Charting control [v2.0]
OpenGL game tutorial in C++

Re: Bit Shift and Mask

Iain Clarke, Warrior Programmer23-Jul-09 9:17

Iain Clarke, Warrior Programmer

23-Jul-09 9:17

That article Cedric pointed you at is great, but doesn't cover bit fields, which is what I'd use in your place.

Not by a compiler, so take this with healthy doubt over the exact syntax, but you can read a book, right?

struct {
  union
  {
     unsigned char Byte;
     struct {
       unsigned char Flag1 : 1;   // : 1 means take 1 bit
       unsigned char Option1 : 2;   // : 1 means take 2 bits
       unsigned char Flag2 : 1;   // : 1 means take 1 bit
       unsigned char Flag3 : 1;   // : 1 means take 1 bit
       unsigned char Flag4 : 1;   // : 1 means take 1 bit
       unsigned char Flag5 : 1;   // : 1 means take 1 bit
       unsigned char Flag6 : 1;   // : 1 means take 1 bit
     } Bits;
   } Flags;
   unsigned char Checksum;
   unsigned short int Sequence;
} PacketHeader

You can use it like:

PacketHeader packet;
ReadPacketSomehow (packet);
if (packet.Flags.Bits.Flag3)
{
   ....
}
if (packet.Flags.Bits.Option3 == 3)  // 2 bits, 0..3
{
   ....
}

Hope that helps you,

Iain.

Re: Bit Shift and Mask

resolvequestion23-Jul-09 9:59

resolvequestion

23-Jul-09 9:59

@ Cedric Moonen - Thanks for the link will look into that...

@ Iain Clarke -- Thats what exactly how I coded and it was working fine.... but than coding standard dosent allow bit fields... so now I have to redo .... and I have very short time to get this thing converted.... (they recommended to use shift and mask... ) Frown | :(

Sorry forgot to mention earlier that I cant use bit fields.... Please can someone help me with this....
THANKS!!!!

Re: Bit Shift and Mask

Iain Clarke, Warrior Programmer23-Jul-09 20:46

Iain Clarke, Warrior Programmer

23-Jul-09 20:46

If you can't use bitfields, then the article Cedric pointed you at will tell you all you ever wanted to know about >>, and &.

Certainly more than I'll type as an answer.

Iain.

Re: Bit Shift and Mask

CPallini23-Jul-09 10:30

CPallini

23-Jul-09 10:30

Hey man, you haven't a Option3 in your union.
Big Grin | :-D

BTW: welcome back!

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]

Re: Bit Shift and Mask

Iain Clarke, Warrior Programmer23-Jul-09 20:49

Iain Clarke, Warrior Programmer

23-Jul-09 20:49

I did say I wasn't by a compiler, and the reader should take my answer with a large dose of doubt. Lucky, eh...

I already had to edit it, because I had too many bits (9) to start with...

I've been lurking a while, but the questions were either already ably answered, or I couldn't think of anything polite to reply with. "You couldn't find your arse with elbows, Go get another career" isn't the most helpful answer, and a hint that I should avoid an answer. Don't want to be another Outlaw!

Iain.

Re: Bit Shift and Mask

CPallini23-Jul-09 10:27

CPallini

23-Jul-09 10:27

struct PacketHeader ph;
unsigned char firstbit  = (ph.flags & 1);
unsigned char secondbit = ((ph.flags >> 1) & 1);
unsigned char thirdbit  = ((ph.flags >> 2) & 1);
unsigned char fourthbit = ((ph.flags >> 3) & 1);
unsigned char remaining = (ph.flags >> 4);

what happens in following code exactly? [modified]

sam_psycho23-Jul-09 5:52

sam_psycho

23-Jul-09 5:52

what happens with if condition in following code?

int function(int i)
{
 printf("inside function");
return 0;
}

int main()
{
   if(function)
   printf("hi");
  else
  printf("bye");
}

and output is only
hi

why compiler doesn't complaints about wrong function call?
Confused | :confused:

modified on Thursday, July 23, 2009 12:08 PM

Re: what happens in following code exactly?

Code-o-mat23-Jul-09 6:01

Code-o-mat

23-Jul-09 6:01

What is fun in your code? Is that suposed ot be:

if (function) ...

?
If so, then the answer is simple, in your if the address of the function will be checked against zero, and since it is not zero, it will come out as TRUE thus, you get "hi".

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Re: what happens in following code exactly?

sam_psycho23-Jul-09 6:11

sam_psycho

23-Jul-09 6:11

yes.. it's

if(function)

and thanx ..I got it.

Re: what happens in following code exactly?

Iain Clarke, Warrior Programmer23-Jul-09 9:06

Iain Clarke, Warrior Programmer

23-Jul-09 9:06

Your function doesn't get called.

I think you mean:

if (function (1234))
...

But instead you're checking if the pointer to function is not 0, which it isn't, so it counts as true, so you get "hi".

Iain.

Re: what happens in following code exactly?

Joe Woodbury23-Jul-09 10:44

Joe Woodbury

23-Jul-09 10:44

In more detail, a procedural function name in C/C++ is a pointer to a function (a memory address). This is how you can pass one function to another function (like with the CRT qsort() function.) So in your if statement, you are checking whether function exists, which it does. To call a function, you have to use the parentheses syntax, i.e. function(1).

[mfc] restart other process

rahuljin23-Jul-09 5:51

rahuljin

23-Jul-09 5:51

hello,

i created 2 c++ applications, one is win32 and other is mfc. i want to restart the win32 process using mfc application. please tell me how to do this ??

also i want to run only 1 instance of process of both the processes. please suggest ??

btw thanks.

Re: [mfc] restart other process

ThatsAlok23-Jul-09 6:05

ThatsAlok

23-Jul-09 6:05

rahuljin wrote:
i created 2 c++ applications, one is win32 and other is mfc. i want to restart the win32 process using mfc application. please tell me how to do this ??

also i want to run only 1 instance of process of both the processes. please suggest ??

killprocess and startexecute

Re: [mfc] restart other process

rahuljin23-Jul-09 7:01

rahuljin

23-Jul-09 7:01

please explain a bit. i can find good info about the killprocess.

Re: [mfc] restart other process

Code-o-mat23-Jul-09 6:11

Code-o-mat

23-Jul-09 6:11

1. CreateProcess[^] or ShellExecute[^]
2. Google is your friend, but look at this[^].

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Re: [mfc] restart other process

rahuljin23-Jul-09 6:52

rahuljin

23-Jul-09 6:52

createprocess() can start a process but cannot restart a running process.

Re: [mfc] restart other process

Code-o-mat23-Jul-09 7:09

Code-o-mat

23-Jul-09 7:09

Sorry, i thought by "restart" you meant that the process got killed/exited by someone else, for example by a user action and you wanted to restart it again.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

Re: [mfc] restart other process

Rajesh R Subramanian23-Jul-09 7:55

Rajesh R Subramanian

23-Jul-09 7:55

I just replied to your yesterday's post. Ignore it. Answer me here: What *exactly* are you trying to achieve. Why restart a Win32 Process? Why use both Win32 and MFC? None of this makes sense to me.

We may probably be able to suggest you a much better way of doing it, but only if you explain what are you trying to do.

It is a crappy thing, but it's life -^ Carlo Pallini

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