Re: shared memory between processes?? - C / C++ / MFC Discussion Boards

Change the background color of a static text control

Daniel Strigl4-Nov-02 1:24

Daniel Strigl

4-Nov-02 1:24

How to change the background color of a static text control (IDC_STATIC) in a dialog?

Daniel Wink | ;)

---------------------------
Never change a running system!

Re: Change the background color of a static text control

Michael P Butler4-Nov-02 1:46

Michael P Butler

4-Nov-02 1:46

Look up WM_CTLCOLOR on MSDN.

Michael

Life’s not a song.
Life isn’t bliss.
Life is just this.
It’s living. -- Buffy the Vampire Slayer: Once more, with feeling

Semaphore wait and signal!!!!

tongc4-Nov-02 1:13

tongc

4-Nov-02 1:13

Hi!
I've encounter the following problem!

<br />
Writec pseudo code using semaphore function wait and signal to solve the following problem:<br />
<br />
A computer system has a pool of N idential printer attached.  Processes that wish to print must obtain an available printer.  Write two functions:<br />
<br />
int getPrinter(void);<br />
void releasePrinter(int printerID);<br />
<br />
getPrinter obtains an availble printer from the pool of N printers and return the printer number (0 to N-1) as its result.  releasePrinter takes a printer number and makes it available for use by other processes.<br />

Here is what i attempt at it

#define N //number of printer;
int numberOfPrinter = N;
int printer[N] //array of N printer;

getPrinter(void)
{
if numberOfPrinter > 0 Then
set printer[numberOfPrinter-1] = used
return numberOfPrinter-1
else
Block
}

releasePrinter(int printerID)
{
numberOfPrinter++;
set printer[printerID] = not used
}

Could you please give me any comment or any advise regarding above problem!

Thanks

Re: Semaphore wait and signal!!!!

Gary Wheeler4-Nov-02 7:33

Gary Wheeler

4-Nov-02 7:33

<no_homework_rant>
The purpose of this forum is to help answer programming questions related to Visual C++, not to find people to do your homework for you!
</no_homework_rant>

Software Zen: delete this;

CListCtrl Focus???

Daniel Strigl4-Nov-02 1:02

Daniel Strigl

4-Nov-02 1:02

How to make that a list control (CListCtrl) never lost the focus?

I have a dialog with a list control and some buttons, and I want that the list box never lost the focus. When I click on any control or on the dialog, the focus will be holed by the list control.

Daniel Wink | ;)

---------------------------
Never change a running system!

Re: CListCtrl Focus???

Andreas Saurwein4-Nov-02 6:49

Andreas Saurwein

4-Nov-02 6:49

First, this is a bad idea. Redesign your app.
Second, process the WM_SETFOCUS, WM_KILLFOCUS messages in all your dialogs controls if you really need to ignore all UI guidelines.

I keep submitting “VB” as a Priority-1 bug, but apparently no one here knows how to fix it. Nick Hodapp, Semicolon

shared memory between processes??

Anonymous4-Nov-02 1:01

Anonymous

4-Nov-02 1:01

In win32, what mechanism allow procesess to share a region of memory? The only method i'm aware of is MapViewOfFile() ?? Is there any idea?

Thanks

Re: shared memory between processes??

Paul M Watt4-Nov-02 5:24

Paul M Watt

4-Nov-02 5:24

Anonymous wrote:
The only method i'm aware of is MapViewOfFile() ?? Is there any idea?

That will create a memory mapped file which is the best method for doing any sort of high speed communication or communication that may create a large number of buffers.

Or you could use GlobalAlloc to create a HGLOBALs with the GMEM_MOVEABLE flag set. This will allocate memory in the pages that are shared across all processes. You will only need to call GlobalLock in order to gain access to the memory from another process. One of the difficulties with this method is that you will need to send a message or do something else to transfer the handle of the HGLOBAL between your two processes.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: shared memory between processes??

ian mariano4-Nov-02 7:31

ian mariano

4-Nov-02 7:31

There are several techniques:

Pipes[^]

You could use the VMM Virtual* functions (similar to Global* memory functions) which are more optimized for > 4MB memory: Working with Pages[^].

More:
Using Shared Memory in a Dynamic-Link Library[^]
Creating Named Shared Memory[^]
CreateSharedMemory[^]

Hope that helps.

"The greatest danger to humanity is humanity without an open mind."
- Ian Mariano - http://www.ian-space.com/

What reports can use in VC instead of Crystal?

LaFlour4-Nov-02 0:56

LaFlour

4-Nov-02 0:56

What kind of reports can use in VC instead of Crystal?
Do u know ones? Confused | :confused:

allowable instruction in kernel mode!!

Anonymous4-Nov-02 0:44

Anonymous

4-Nov-02 0:44

Hi!
I have the following instruction:

1)Disable all interupts
2) Read the time of day clock
3)Set the time of day clock
4)Change memory map

What of the above instruction should be only allowed in the kernel mode!

I've come with solution is that number 1 should only be allow in the kernel mode. However i dont quite get "change memory map" meaning. Could anyone plse perhap explain the term and give comment about the above question!

Regard,

Re: allowable instruction in kernel mode!!

Paul M Watt4-Nov-02 5:27

Paul M Watt

4-Nov-02 5:27

I dont understand the context for this question, so it seems to me that there is not enough information to answer your question. Do you know what your memory map is for, or who creates it?

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

How Can I Set Items' Images of Toolbar

IMiracle4-Nov-02 0:39

IMiracle

4-Nov-02 0:39

Under Vc++ 6.0 and MFC, how can I set items' images of the toolbar.These images were saved as .bmp or .ico. And I known how to load the .bmp to CBitmap.

Help me!!!
Help me!!!
Help me!!!

Re: How Can I Set Items' Images of Toolbar

viliam4-Nov-02 0:55

viliam

4-Nov-02 0:55

Try this:
CToolBar::LoadBitmap()
CToolBar::SetBitmap()

or call CToolBar::GetToolBarCtrl()
And then access single items – more: CToolBarCtrl member functions
Viliam

Re: How Can I Set Items' Images of Toolbar

IMiracle4-Nov-02 1:03

IMiracle

4-Nov-02 1:03

I means that one item have its own one image.
A toolbar has several images, not one bitmap to all items.

"multi-master"

Anonymous4-Nov-02 0:41

Anonymous

4-Nov-02 0:41

I've got this for my tute question!

A large organisation has offices in several countries around the world. Explain why it is desireable for the organisation's directory service to be "multi-master"

Could any one please enlighten me! Thanks.

Re: "multi-master"

Maximilien4-Nov-02 2:52

Maximilien

4-Nov-02 2:52

Huh ?! I assume that it got to be related to the Active Directory thing, just read about it, it's bound to be explained somewhere in there .

Max.

Generating a short delay (a few ms)

LittleYellowBird3-Nov-02 23:58

LittleYellowBird

3-Nov-02 23:58

I'm trying to generate a short delay of just a few ms, which I need because I am controling a box on the serial port which is very slow and the input is un-buffered so I need to pad the data.

I am using Sleep(x), where x is the number of ms. However, I get a much longer delay than I need, ie Sleep(1) gives me 70ms!

Anyone got any ideas of how I can generate a short delay reliably?

Thanks,

Ali

Re: Generating a short delay (a few ms)

Vagif Abilov4-Nov-02 0:30

Vagif Abilov

4-Nov-02 0:30

You can try Sleep(0), it causes the thread "to relinquish the remainder of its time slice to any other thread of equal priority that is ready to run."

Vagif Abilov
MCP (Visual C++)
Oslo, Norway

Hex is for sissies. Real men use binary. And the most hardcore types use only zeros - uppercase zeros and lowercase zeros.
Tomasz Sowinski

Re: Generating a short delay (a few ms)

LittleYellowBird4-Nov-02 2:21

LittleYellowBird

4-Nov-02 2:21

Thanks for the suggestion, I'm not sure it will give consistent enough results - I'll look in to it though.

Thanks,

Ali

Re: Generating a short delay (a few ms)

Gary Kirkham4-Nov-02 11:26

Gary Kirkham

4-Nov-02 11:26

You didn't say what operating system you were using. I doesn't answer your question, but you may find the following article interesting...

http://www.codeproject.com/system/simpletime.asp

Gary Kirkham

A working Program is one that has only unobserved bugs

Re: Generating a short delay (a few ms)

LittleYellowBird5-Nov-02 3:15

LittleYellowBird

5-Nov-02 3:15

Looks like an interesting article, thanks for the tip.

Cheers,

Ali

Re: Generating a short delay (a few ms)

viliam4-Nov-02 0:33

viliam

4-Nov-02 0:33

I am afraid there is no way how to suspend process on accurate time.
(Windows are not real - real-time system)
The easiest way is use traditional way – run some loop
(and be on appropriate priority)
And check time...
Something like:
.
.
dwA = GetTickCount();
while(1)
{
dwB = GetTickCount();
if( (dwB-dwA) >= dwTimeout)
break;
}

This is not nice way but sometime can help.
Anyway times about 1 ms are probably unreachable.
Viliam

Re: Generating a short delay (a few ms)

LittleYellowBird4-Nov-02 2:18

LittleYellowBird

4-Nov-02 2:18

Using GetTickCount() is a great idea. I just checked the help and it returns the number of ms since start up, so as you suggest I can use it in a loop to make a basic timer.

I agree that 1 ms is impractical but if I try for 1 ms and get 2 ms or 3ms or even 4ms, that woud be far better than 70+ ms!

Thanks for the help,

Ali

Re: Generating a short delay (a few ms)

Brigg Thorp4-Nov-02 2:28

Brigg Thorp

4-Nov-02 2:28

One thing you have to watch out for. If you keep your computers on all the time, the rollover of the time could effect your calculation (e.g the start time could be greater than the end time). You just have to put in checking for this.

Brigg Thorp
Software Engineer
Timex Corporation

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