C / C++ / MFC

1-Dec-05 6:46

I need to implement a function to read application event logs in realtime. I have done this for our Unix server in Perl, but do not have the option of installing Perl on our Win32 production servers.

I have scoured (literally for days) the internet looking for any information on the best way to do this in C++ but haven't found anything! Any assistance or direction is greatly appreciated.

What I need to do is read these event logs and then send alerts or trigger other functions based on specific events. The log files are updated 10-100 times a minute depending on how many users are connected to the server so I need to continue monitoring the log even if I fork out to respond to event01. Make sense?

Thank you!

--Kenny

Jim Crafton1-Dec-05 7:51

Jim Crafton

1-Dec-05 7:51

Sounds like you want to create an Event object ( see CreateEvent()[^]) wait on it in on place (thread) and then signal it from another when the log write occurs.

You can look into NT's event logging API's but I don't know if there are any performance issues for what you're intendending.

You can create teh event with a name, so that more than one process can wait on it.

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SELECT * FROM User WHERE Clue > 0
0 rows returned

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Kenny03231-Dec-05 8:21

1-Dec-05 8:21

That definately seems to take care of the second part of my problem. Thank you!

Now do you have any advice on the most effecient way to read a log file that is being updated almost constantly? Smile | :)

Jim Crafton1-Dec-05 8:29

Jim Crafton

1-Dec-05 8:29

Well just off the top of my head, if you're worried about access speed/io to the file, you could create a memory mapped file and then use that - then one process can write, another can read, without having to contantly open/close the file all the time.

¡El diablo está en mis pantalones! ¡Mire, mire!

Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!

SELECT * FROM User WHERE Clue > 0
0 rows returned

Save an Orange - Use the VCF!

Kenny03231-Dec-05 9:01

1-Dec-05 9:01

This is a bit too much C++ as I am mostly a Perl/PHP developer. I was hoping for something that I could do with simple file I/O. =)

I will look into it however.

Thanks!

Jim Crafton1-Dec-05 9:29

Jim Crafton

1-Dec-05 9:29

Well then you could just open the file, and read from the end of it. Maybe keep track of the file size from the previous open, and compare to it's current size, and then read in the difference from the end. That's slower, and less complex, but makes heavier duty use of disk IO. Don't know how big a deal that is for you.

¡El diablo está en mis pantalones! ¡Mire, mire!

Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!

SELECT * FROM User WHERE Clue > 0
0 rows returned

Save an Orange - Use the VCF!

David Crow1-Dec-05 9:29

David Crow

1-Dec-05 9:29

Kenny0323 wrote:
This is a bit too much C++...

Actually, memory mapped files have nothing to do with C++. One thread/process will need to call CreateFileForMapping() (all others will need to call CreateFile()). Call CreateFileMapping(), then use the pointer returned from calling MapViewOfFile().

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David Crow1-Dec-05 8:27

David Crow

1-Dec-05 8:27

Will NotifyChangeEventLog() help?

"Take only what you need and leave the land as you found it." - Native American Proverb

Kenny03231-Dec-05 9:03

1-Dec-05 9:03

I looked into this, but this seems tailored to logs that use the same format (and actually write to) the windows event logs. Which our system does not.

Thank you, though.

*** I guess I should have been more clear. These are *not* standard Windows App Event Logs, they are flat text .LOG files.

How to change color of text on the About dialog ?

David Crow1-Dec-05 9:24

David Crow

1-Dec-05 9:24

Kenny0323 wrote:
I looked into this, but this seems tailored to logs that use the same format (and actually write to) the windows event logs.

When you said "application event logs", that only means one thing to me.

Kenny0323 wrote:
These are *not* standard Windows App Event Logs, they are flat text .LOG files.

You'll need to make sure that read and write operations are synchronized. Otherwise, one could preempt the other and you'd have a big mess to clean up.

"Take only what you need and leave the land as you found it." - Native American Proverb

quangpk1-Dec-05 6:37

quangpk

1-Dec-05 6:37

How to change color of text and background on the About dialog ?

Dialog tabbing

Jader891-Dec-05 5:27

Jader89

1-Dec-05 5:27

Is there a method that, when you select something from a drop down menu, will automaticly go to another dialog edit control box? Like when you hit tab, so that the number, or whatever is inside, is highlighted and ready to be chaged. It seems there should be, and i dont think im wording it right in my google searches.

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Re: Dialog tabbing

Taka Muraoka1-Dec-05 6:12

Taka Muraoka

1-Dec-05 6:12

Why not just call SetFocus() in the menu handler to set the focus to the edit control? You might need to do a SET SEL as well.

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Re: Dialog tabbing

Jader891-Dec-05 6:23

Jader89

1-Dec-05 6:23

Yes, setsel was what i was looking for, thank you.

"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.

MFC Help !....Draw a focus rectangle aroud image

inbakumar.G1-Dec-05 3:32

inbakumar.G

1-Dec-05 3:32

Hi,

I developed a thumbnail viewer using doc / view architecture and GDI+. I have done the rotate, flip options, but when we choose or click any thumbnail image, I want to draw the focus rectangle around the image instead of bluecolor shadow selection. Can u help me Confused | :confused:

...... if it is possible send a sample code.

Thanking you.

Regards,
Inbakumar.G

-- modified at 9:37 Thursday 1st December, 2005

How do I create expanding dialog

Jethro631-Dec-05 3:05

Jethro63

1-Dec-05 3:05

Greetings:

I am trying to create one of those dialog boxes that have an "expand and contract" feature. I'm sure you have all seen them: The box has a smaller "fixed" segment, say, at the top, but there is a control, like a button that says "More >>" that causes it to expand at the bottom and reveal additional controls and options.

I think I understand that I need to create TWO dialog resource templates, one representing the fixed top portion and a second that is layed out at the top identical to the first dialog but larger at the bottom with the extra controls. Then, when the "More >>" button is pushed, somehow, I swap the old resource template for the new one.

Its the "somehow" part that has me stumped. I have two questions:

1. How do I keep the dialog open while I swapp templates? (Or can I? Is this done some other way?)
2. How do I do this trick while keeping the fixed part of the dialog positioned on the screen? In otherwords, I don't want the the new, larger, dialog window trying to re-center itself. I want the top part to stay put and the swap operation to appear as though the dialog has literally expanded at the bottom.

If it turns out that I have to essentially close the old dialog and re-open it with the larger template, then I would like to preserve the illusion that the original dialog is simply expanding to revela more controls.

I guess that is a pretty loaded request but any assistance would be greatly appreciated.

Thank you,
Mark

khan++1-Dec-05 3:24

khan++

1-Dec-05 3:24

You can create a second dialog resource and attach a class to it. Create it as modeless, and a child of the main dialog. When user presses the more button, show it using ShowWindow(SW_SHOW); and position it correctly using SetWindowPos() etc. Similarly when button is pressed again, check if it is visible: m_ChildDialog.ShowWindow(! m_ChildDialog.IsWindowVisible());
Hope that helps.

this is this.

Jethro631-Dec-05 3:31

Jethro63

1-Dec-05 3:31

Hi Khan:

Is there anyway to do this and still keep the dialogs modal?

Also, what will happen if the user moves the new window? Won't the old window be revealed behind it?

Thanks for your help!
Mark

khan++1-Dec-05 3:38

khan++

1-Dec-05 3:38

If you need to scroll the controls at the bottom into view, then create all the controls on the main dialog, and increase/decrease the height of the dialog in a loop using SetWindowPos().

this is this.

grigsoft1-Dec-05 3:30

grigsoft

1-Dec-05 3:30

I've done this by dinamically hiding\disabling set of controls + resize of the dialog itself. If your extra portion is in the middle, this would need some efforts to reposition other controls, but I have done this too before.

Igor Green
http://www.grigsoft.com/ - files and folders comparison tools

grigsoft1-Dec-05 3:50

grigsoft

1-Dec-05 3:50

You may also check these:
http://www.codeproject.com/dialog/dlgexpand.asp[^]
http://www.codeproject.com/dialog/dlgboxtricks.asp[^]

Igor Green
http://www.grigsoft.com/ - files and folders comparison tools