Managed C++/CLI

Luc Pattyn23-May-09 12:35

Luc Pattyn

23-May-09 12:35

Unbe Kant wrote:
would that be one of those categories?

absolutely not. as I understand it, you have a lot of data (filling almost all the memory)
and a heavy computation, nothing extremely dynamic or real-time oriented.

The one thing you must avoid is having your data copied, since 1) that slows things down, and 2) that requires extra memory (worst case: twice as much).

I still believe allocating on the managed side is the right way to go. I can't imagine Intel insists on allocating the data arrays themselves. They must accept pre-existing arrays, so allocate them in the managed world, use GCHandle to pin them down and get their pointer, then pass that to the native code, where Intel should accept them as if they were allocated with native code outside the Intel library. (If the Intel library would need some working space, which remains entirely hidden from the outside, so be it).

There is one caveat: managed memory blocks larger than some 80-85KB get allocated on the "large-object heap" which never gets compacted (moving the data would be too expensive). If lots of such blocks, all with different sizes, would be allocated and deallocated in random order, memory could become fragmented preventing a future allocation although sufficient free memory is available.

The relevance of a fragmentation risk depends on the variability of your array sizes, and the frequency of allocating and freeing such arrays. The subject is carefully avoided in all but the deepest documentation and discussions.

If, for some reason, you have to allocate all memory on the native side, you will have to:
- either provide managed but pointer-based code to fill the array yourself;
- or rely on one of the Marshal.Copy() overloads to fill part of the arrays (doing it by parts to prevent you needing twice the memory), maybe row-by-row.

BTW: I trust both Intel's library and yourself are sufficiently performance-aware to avoid multi-dimensional arrays; in my experience a little effort to linearize them immediately pays off.

Smile | :)

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Unbe Kant23-May-09 13:22

Unbe Kant

23-May-09 13:22

>as I understand it, you have a lot of data (filling almost all the memory)
>and a heavy computation, nothing extremely dynamic or real-time oriented.
Precisely.

> I still believe allocating on the managed side is the right way to go.

Ok, convinced, I believe you and will make it so.

> I can't imagine Intel insists on allocating the data arrays themselves

Of course, it doesn't. Please forgive me if I didn't made this point clear enough: The application must allocate the memory and pass the pointer all along with the number of elements (eg. m and n for a m*n matrix)

> BTW: I trust both Intel's library and yourself are sufficiently performance-aware
> to avoid multi-dimensional arrays; in my experience a little effort to linearize them immediately
> pays off.

Sure, I wrote about multi-dimensional matrices, not arrays Wink | ;-)

Again thank you very much for taking the time helping me with your input. I shall now start experimenting Wink | ;-)

Regs

UK

led mike27-May-09 5:01

27-May-09 5:01

Luc Pattyn wrote:
IMO the rumors of C++/CLI being much better at interop than C# are highly overrated.

Luc, I hope you won't mind if I defer to these fellows facts as opposed to your opinion? Wink | ;)

While there is no question that the Microsoft® .NET Framework improves developer productivity, many people have some concern regarding the performance of managed code. The new version of Visual C++® will allow you to set aside these fears. For Visual Studio® 2005, the C++ syntax itself has been greatly improved to make it faster to write. In addition, a flexible language framework is provided for interacting with the common language runtime (CLR) to write high-performance programs.
Many programmers think that C++ gets good performance because it generates native code, but even if your code is completely managed you'll still get superior performance. With its flexible programming model, C++ doesn't tie you to procedural programming, object-oriented programming, generative programming, or meta-programming.

Another common misconception is that the same kind of superior performance on the .NET Framework can be attained regardless of the language you use—that the generated Microsoft intermediate language (MSIL) from various compilers is inherently equal. Even in Visual Studio .NET 2003 this was not true, but in Visual Studio 2005, the C++ compiler team went to great lengths to make sure that all of the expertise gained from years of optimizing native code was applied to managed code optimization. C++ gives you the flexibility to do fine tuning such as high-performance marshaling that is not possible with other languages. Moreover, the Visual C++ compiler generates the best optimized MSIL of any of the .NET languages. The result is that the best optimized code in .NET comes from the Visual C++ compiler.

http://msdn.microsoft.com/en-us/magazine/cc163855.aspx[^][^]

Wait Luc, there's more

Summary: Explore the design and rationale for the new C++/CLI language introduced with Visual C++ 2005. Use this knowledge to write powerful .NET applications with the most powerful programming language for .NET programming.

C++: The Most Powerful Language for .NET Framework Programming[^]

MORE!!!

Some people think that Microsoft forgets C++ playing with C#, but C++ is still widely used language. Could you comment it?

Microsoft has absolutely *not* forgotten C++. Most shrink-wrap applications are C++ because it's the smallest, tightest way to build apps and requires the least support from the OS itself. There is tons of existing C++ code in the world and Microsoft has implemented pure magic in the managed extensions for C++. MC++ allows you to flip a compiler switch, recompile your C++ code and begin producing and consuming .NET types immediately, all without changing your unmanaged types. In addition, the MC++ IJW (It Just Works) technology provides the lowest overhead interop layer between managed and unmanaged code, making it the best way to bridge the gap between the two technologies. Also, VS.NET 2003 provides a C++ compiler that compiles unmanaged C++ code down to smaller and faster code than ever before, while increasing ANSI C++ compliance to the highest level of any C++ compiler that I know of. I can't say enough good things about Microsoft's continued support for C++. I don't know of anyone doing more.

Interview with Chris Sells[^]

Luc Pattyn27-May-09 5:50

Luc Pattyn

27-May-09 5:50

Hi Mike,

there is a lot you wrote/copied/linked to that I agree with. Even when some of it may sound a little biased (MS has to promote .NET, has to make clear what the position is with repect to C++, it is only normal compilers and code generators get improved, etc).

However it is besides the point I was making or trying to make: once it has been decided a mixture of managed code and native code is needed (maybe because of existing native code), making the two worlds cooperate often can be achieved with C# and P/Invoke as efficiently and with the same performance as can be done with C++/CLI. I am not saying C# is better or worse than C++/CLI, I am only referring to its ability to interface well with the native world.

I have been doing a lot of interop over the years, dealing with huge amounts of numeric data going back and forth, and the one thing that really matters performance-wise is the data does not get copied. Well, that can be organized by allocating managed buffers (e.g. int arrays), then passing pointers (I tend to use GCHandle for that, even when sometimes a simple fixed would suffice).

Example: I created an image processing library using run-time generated assembly code (including MMX/SSE for Intel x86 and Altivec for PowerPC) and called from both .NET (C#, using P/Invoke) and Java (using some kind of JNI); the code was not PC specific, it had to run on non-Windows embedded systems too. In the end the SIMD code was almost as fast as a copy operation, so adding one or two copy operations to it would be unacceptable.

Some people claim the best way to call native code from C# is by providing a C++/CLI wrapper, and maybe this is correct for complex data structure situations (not sure), but I object to those anyway. KISS is one of my motto's, and with a KISS interface, C# + P/Invoke works great.

Hence my statement: "IMO the rumors of C++/CLI being much better at interop than C# are highly overrated."

Smile | :)

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Resizing of Labels in Controls

N a v a n e e t h27-May-09 17:22

N a v a n e e t h

27-May-09 17:22

+5 for the links Smile | :)

Navaneeth

How to use google | Ask smart questions

cherrymotion21-May-09 21:23

cherrymotion

21-May-09 21:23

Hi,
can somebody pleas tell me, how to correctly resize controls.
I made up a Windows Forms Control Library Projekt for a simple "status-line" control, with some text
for picture information (labels).
The control has to be able to be dynamically resized (f.e. when user stretches the window of the parent form).
But I do not come up with how to manage that.
I thought I can do it with the scale-function, but somehow alway just the panels are scaled (the text-labels are on two
different panels->upper and lower), the text-size of the labels remain in original size and so can no longer be shown correctly.
Why is that? I mean, when I scale a whole control, the scale function should scale all, or not?
I also tried with the "Resize-Event", so that I shrink /grow the labels manually, but it also didn't work.
And is there an opportunity to find over the Resize-Event, how MUCH the window grew / shrank - I think you should have a
factor to inherit the growth on somehow.
Maybe my mistake is just from false properties, but how would you pros manage that?
Thanks in advance,

cherry

N a v a n e e t h21-May-09 21:54

N a v a n e e t h

21-May-09 21:54

Read about Anchor[^].

Smile | :)

Navaneeth

How to use google | Ask smart questions

cherrymotion21-May-09 22:16

cherrymotion

21-May-09 22:16

I know about the anchoring, and I used it.
But as I said, the control ist anchored nicely, but the labels (text) remain as big as they are.
There are so many attributes concerning "sizing", so that I maybe always set on property not correctly.
How does anchoring, docking, autosizing and scaling work together - I found there no good descriptions in
the web.
I found that http://msdn.microsoft.com/en-us/library/ms171729.aspx[^]
You see, they write
"Note The Label control is the exception to this rule. When you set the value of a docked Label control's AutoSize property to true, the Label control will not stretch."
But how do I get the stretching then?

led mike22-May-09 4:26

22-May-09 4:26

cherrymotion wrote:
But how do I get the stretching then?

Why do you need a label control to stretch more than what is required to display the text?

Re: Resizing of Labels in Controls [modified]

cherrymotion22-May-09 8:25

cherrymotion

22-May-09 8:25

Ok, I have it now. Something went wrong with my Auto-Size properties.
But can anyone tell me how to find out from the Control.Resize-Event, with which
factor the Form has been resized?
I have to calculate the space for my pictures an let them dynamically grow and shrink,
but for that I'm sure there is an opportunity to get that factor, isn't it?

Otherwise maybe I should save a rectangle with the current form size and set it then
in relation to the "grown" window parent. But a "resize-factor" would be much nicer I think...

Thanks for your answers, sometimes it is not easy Smile | :)

Luc Pattyn22-May-09 9:40

Luc Pattyn

22-May-09 9:40

Hi,

The Form class already has 4 events regarding resizing: Resize, ResizeBegin, ResizeEnd, SizeChanged. That should cover it I'd say.
However you have to keep the current Size somewhere in order to calculate growth/shrink.

Smile | :)

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modified on Friday, May 22, 2009 3:48 PM

Sending events to main window of another process

parth_patel21-May-09 5:34

Re: Sending events to main window of another process

21-May-09 5:34

Hello everyone,

Does anybody know of a way to send events to another process from the first process in managed C++.
I found an article for the same in C++ but couldn't find one for managed C++.

Thanks,
Parth

led mike21-May-09 5:48

Re: Sending events to main window of another process

21-May-09 5:48

Member 3273983 wrote:
I found an article for the same in C++

Provide a link please. Also explain why that article does not work for you.

parth_patel21-May-09 6:05

Re: Sending events to main window of another process

21-May-09 6:05

Sending a message to the Main Frame Window of Another Application, given only the Process Handle[^]

It is for C++ not managed C++. I want to do it in managed C++ which uses the form class instead of CWin* classes.

led mike21-May-09 7:50

Re: Sending events to main window of another process

21-May-09 7:50

Member 3273983 wrote:
I want to do it in managed C++ which uses the form class instead of CWin* classes.

Yes. C++/CLI allows you to use managed and native code in the same project. So you can in fact use the approach from that article in your managed code. If you don't know how to create a C++/CLI project that supports managed and native code then you need to go read the Introductory CLI articles here on CodeProject.

parth_patel21-May-09 10:58

Re: Sending events to main window of another process

21-May-09 10:58

Thanks for the info. I will look up the tutorials.
-Parth

parth_patel27-May-09 9:23

Re: Sending events to main window of another process

27-May-09 9:23

I had one more question, is the same thing possible to get done with Java windows as target?

Mark Salsbery21-May-09 7:23

Mark Salsbery

21-May-09 7:23

Hook up!

><O>
><O>
><O>

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

Re: Sending events to main window of another process

led mike21-May-09 7:50

Problem getting exact response through webrequest

21-May-09 7:50

Reel me up Scotty!

naveen_bij18-May-09 21:54

naveen_bij

18-May-09 21:54

I have a situation where in i need to send the username and the password to a website and get the confirmation back from the website. Website takes the request in the form of query string.<b> The problem is when i send the request i am not getting the exact response, instead somtimes i get the html code of the website with the response or sometimes i get the url with response. below is the code, can someone please help me with this

mId is the username and mPwd is the password

try
{
String^ lcUrl = "http://login.somewebsite.com/Authorization/";
lcUrl = lcUrl +  mId + "/" + mPwd;
HttpWebRequest^ loHttp = (HttpWebRequest^) WebRequest::Create(lcUrl);
// *** Send any POST data
String^ lcPostData = mId + "/" + mPwd;
loHttp-&gt;Method="POST";
loHttp-&gt;Credentials = CredentialCache::DefaultCredentials;
loHttp-&gt;ContentType = "application/x-www-form-urlencoded";
array&lt;Byte,1&gt;^ lbPostBuffer = gcnew array&lt;Byte,1&gt;(lcPostData-&gt;Length);
lbPostBuffer = System::Text::Encoding::UTF8-&gt;GetBytes(lcPostData);
loHttp-&gt;ContentLength = lcPostData-&gt;Length;
Stream^ loPostData = loHttp-&gt;GetRequestStream();				
loPostData-&gt;Write(lbPostBuffer,0,lbPostBuffer-&gt;Length);
loPostData-&gt;Close();
HttpWebResponse^ loWebResponse = dynamic_cast&lt;HttpWebResponse^&gt; (loHttp-&gt;GetResponse());
Encoding^ enc = System::Text::Encoding::GetEncoding(1252);
StreamReader^ loResponseStream = gcnew StreamReader(loWebResponse-&amp;gt;GetResponseStream(),enc);
lcHtml = loResponseStream-&gt;ReadToEnd();				
loWebResponse-&gt;Close();
loResponseStream-&gt;Close();
MessageBox::Show(lcHtml,"Confirmation",MessageBoxButtons::OK);
}
catch(IOException^ exio)
{				MessageBox::Show(exio-&gt;Message,"Error",MessageBoxButtons::OK);
}
catch(WebException^ webEx)
{				 MessageBox::Show(webEx-&gt;Message,"Error",MessageBoxButtons::OK);
}
catch(Exception^ ex)
{				 MessageBox::Show(ex-&gt;Message,"Error",MessageBoxButtons::OK);
}
return lcHtml;

Naveen

Delegates and Event in VC.Net

savitri18-May-09 19:40

savitri

18-May-09 19:40

Hi All,

I am Savitri here. I am new to this forum and also new to vc.net language.
I am getting confusion in delegates and events in vc.net. Please if any body have documents and examples for this topic please give me. I will read from that. I am not getting any examples in vc.net so i am asking you all. Please do needful for me.
Thanks in advance.

Regards,
Savitri p Smile | :)

Re: Delegates and Event in VC.Net

led mike19-May-09 5:35