C / C++ / MFC Discussion Boards

Luc Pattyn16-Dec-08 2:45

16-Dec-08 2:45

Hi George,

the answer is no; there is no macro/constant giving max length.
However there is a Win32 function that gives you the max length, it is called GetComputerNameEx; just give it a buffer=NULL and a size variable whose value is set to zero. Upon return, read that very same size value, then allocate a sufficiently large buffer, and call GetComputerNameEx again.

BTW: this is a common pattern in Win32: first ask for size, then allocate, then ask for data using the same function.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Fixturized forever. Confused | :confused:

Re: computer name length issue

George_George17-Dec-08 1:55

George_George

17-Dec-08 1:55

Thanks Luc,

I am just surprised there is no such macro defined on Windows as built-in macro. Smile | :)

regards,
George

Re: computer name length issue

Luc Pattyn17-Dec-08 2:27

Luc Pattyn

17-Dec-08 2:27

Some parameters just aren't constant, e.g. they depend on installation choices, available hardware, etc. In these cases you need to actually run some code to determine maximum sizes. Not sure why it would be dynamic in this case, but that is the author's decision after all.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Fixturized forever. Confused | :confused:

Re: computer name length issue

George_George17-Dec-08 2:30

George_George

17-Dec-08 2:30

Macro exists. Here it is.

http://www.codeproject.com/script/Forums/View.aspx?fid=1647&msg=2846296[^]

regards,
George

Re: computer name length issue

Luc Pattyn17-Dec-08 2:34

Luc Pattyn

17-Dec-08 2:34

OK.
does it match the return value when size zero was given?

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Fixturized forever. Confused | :confused:

Re: computer name length issue

George_George17-Dec-08 2:43

George_George

17-Dec-08 2:43

What do you mean match return value? Return value is BOOL. Smile | :)

http://msdn.microsoft.com/en-us/library/ms724301(VS.85).aspx[^]

regards,
George

Re: computer name length issue

Mark Salsbery16-Dec-08 5:37

Mark Salsbery

16-Dec-08 5:37

Your answer is in the link YOU provided

"The length of the name may be greater than MAX_COMPUTERNAME_LENGTH
characters because DNS allows longer names. To ensure that this buffer
is large enough, set this parameter to NULL and use the required buffer
size returned in the lpnSize parameter."

As many others have mentioned, that's the proper way to use the API.

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: computer name length issue

George_George17-Dec-08 1:59

George_George

17-Dec-08 1:59

Thanks Mark!

You mean call this API twice? I showed my understanding of your points in the following pseudo code. Any comments? Does it what you mean?

int size;

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   NULL,
  &size
);

buffer = new char[size+1];

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   buffer,
  &size
);

regards,
George

Re: computer name length issue

Mark Salsbery17-Dec-08 5:00

Mark Salsbery

17-Dec-08 5:00

George_George wrote:
You mean call this API twice?

Yes.

You may want to increment the size variable before the second call...

int size = 0;

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   NULL,
  &size
);

size++;
buffer = new char[size];

GetComputerNameEx(
  __in     COMPUTER_NAME_FORMAT NameType,
   buffer,
  &size
);

Many APIs were designed to be called that way.

If you absolutely must use a static buffer length, in my experience,
a buffer size of 260 (MAX_PATH) has always been large enough.
Doing it as shown above is the safe, correct way, however.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: computer name length issue

George_George17-Dec-08 19:36

George_George

17-Dec-08 19:36

Thanks Mark,

Here is a better solution. Using built-in macro. Any comments?

http://www.codeproject.com/script/Forums/View.aspx?fid=1647&msg=2846296[^]

regards,
George

VLCPlugin2 - Snapshot

kutti16-Dec-08 0:44

kutti

16-Dec-08 0:44

Hi,

I am using VLC plugin 2 Active X control in vc++ sample application.

I can able to see live video, using CVLCPlaylist.add() method call.
How to take snapshot?
Any help ?

Re: VLCPlugin2 - Snapshot

Eytukan16-Dec-08 6:29

Eytukan

16-Dec-08 6:29

printscreen button Roll eyes | :rolleyes:

OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus

Best wishes to Rexx[^]

Re: VLCPlugin2 - Snapshot

kutti16-Dec-08 17:27

kutti

16-Dec-08 17:27

Hi,
Thanks for your reply.

how to set the snapshot path?
is there any default path for snapshot?

I tried your suggestion for taking snapshot.
But it is not working.
Is there any possibility to use CVLCVideo::takeSnapshot() ?

Inheritance in C

Chandrasekharan P15-Dec-08 23:39

Chandrasekharan P

15-Dec-08 23:39

I dont know if this is the right forum to post this query

i wanted to know if we can achieve inheritance and encapsulation in C.

Re: Inheritance in C

Stuart Dootson15-Dec-08 23:50

Stuart Dootson

15-Dec-08 23:50

With some effort, you can mimic inheritance.

Use of structs effectively gets you encapsulation.

Re: Inheritance in C

Chandrasekharan P15-Dec-08 23:54

Chandrasekharan P

15-Dec-08 23:54

a little more explanation will be of great help.

Re: Inheritance in C

David Crow16-Dec-08 2:40

David Crow

16-Dec-08 2:40

struct base<br />
{<br />
};<br />
<br />
struct derived : public base<br />
{<br />
};

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

Re: Inheritance in C

C^hris L^osinger16-Dec-08 6:37

C^hris L^osinger

16-Dec-08 6:37

? struct derived : public base

that is not C

image processing toolkits | batch image processing

Re: Inheritance in C

David Crow16-Dec-08 8:25

David Crow

16-Dec-08 8:25

I see that I failed to see that the OP wanted a solution in C. D'Oh! | :doh:

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

Re: Inheritance in C

CPallini16-Dec-08 0:03

CPallini

16-Dec-08 0:03

Why don't you use C++, instead?

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: Inheritance in C

Chandrasekharan P16-Dec-08 0:20

Chandrasekharan P

16-Dec-08 0:20

that is a good qusestion.. Smile | :)

i can certainly use C++. but its just the curiosity to know how it can be done. i actually saw in a forum that inheritance can be acheived in c but there was no practical example available in the forum, there was only some explanations that was not satisfactory. so wanted to know more about it . if you could provide that would be great.

Re: Inheritance in C

Jijo.Raj16-Dec-08 0:16

Jijo.Raj

16-Dec-08 0:16

Just read this - Object Oriented Programming in C[^]. Implementing OOP behavior in C is not tough because cfront - the first C++ compiler does compilation by translating C++ source to C and then compile it. If you are insterested, have a look at the cfront source from here[^].

Regards,
Jijo.

_____________________________________________________

http://weseetips.com[^] Visual C++ tips and tricks. Updated daily.

CMenu -> GetMenuString -> Get text and shortcut key seperate

karhong15-Dec-08 22:57

karhong

15-Dec-08 22:57

Hi, I've created an owner draw Menu and i wanted to get the text and the shortcut key seperately. Any idea??

By calling below code, it will get both text and shortcut key and put inside a string.

COwnerMenu OwnerMenu; //this is inherit from CMenu
OwnerMenuPointer->GetMenuString(i, str, MF_BYPOSITION);

I tried to seperate it by searching "Ctrl+"
But as the shortcut key might not started with Ctrl+, so i cant use this method..
Can i get the shortcut key and also the text seperately by using the pointer "OwnerMenuPointer" ??

I've search through net and I cant find any solution
Any help would be appreciated.

Regards,
KH

good

Re: CMenu -> GetMenuString -> Get text and shortcut key seperate

L. Madhavan15-Dec-08 23:01

L. Madhavan

15-Dec-08 23:01

The shortcut text is separated from the menu item text by a tab character. Just search for \t within the menu string and split it at that point.

Re: CMenu -> GetMenuString -> Get text and shortcut key seperate

karhong15-Dec-08 23:04

karhong

15-Dec-08 23:04

OH THANKS!!!
IT WORKS !!

good

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