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Post the code.
John Nawrocki
Chief Technical Advisor
Custom Molded Products
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NB: As indicated in a reply the issue has been solved. The DirectX module was changing the floating point precision.
A colleague is calling the constructor of a class which takes two doubles as arguments. Each argument he passes is the sum of two doubles:
CGridPoint( a + b, c + d)
The class object stores the two values internally. When he views the result he sees that the values have been rounded to 1 decimal place.
The values are not so large that this would be expected. Here are example:
a = 44.445472717
b = 724631.800000000
a + b = 724676.250000000
In other words he passes in 44.445472717 + 724631.800000000 as the first argument to the constructor and the result is stored internally and is seen to be 724676.250000000.
Does anyone know the cause of this rounding?
BTW he uses VS2008. This works in VS2010.
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What is the code he is using to store the values and also to display them?
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He is examing the property of the CGridPoint class using the debugger. He also confirms that the results look wrong when used. He displays a 2D representation of a Geophysical survey vessel and streamers on his screen, and position error ellipses are wrong, which is how he found this issue.
The code is C++ of course. He has rewritten like this:
CGridPoint gpt2 = gpt[i].Rotate(m_gptEllipseAngle);
gpt2.m_fEasting += gptLocation.m_fEasting;
gpt2.m_fNorthing += gptLocation.m_fNorthing;
pts[i] = ViewPoint(gpt2);
And it still fails. The original would have been something like:
CGridPoint gpt2 = gpt[i].Rotate(m_gptEllipseAngle);
pts[i] = ViewPoint(CGridPoint(gpt2.fEasting + gptLocation.m_fEasting, gpt2.fNorthing + gptLocation.m_fNorthing ));
The above might have a typo or two, not sure, I rewrote it here without compiling it.
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I can't see the CGridPoint class in ATL or MFC; is this a Microsoft or home produced class?
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He has found the cause. A call to DirectX was changing the floating point (double) precision ..
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I think we need to see CGridPoint. I suspect that it is explicitly rounding things to 2dp (or could even be quarter-points from the particular example you gave).
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A quick look at the rounded result (7xxx.25) shows it to have about the precision we'd expect from float. I'd wager that there's an explicit or implicit conversion to float and back again hidden in there somewhere. Looks like you'll have to pick through it line by line.
Peter
Software rusts. Simon Stephenson, ca 1994.
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Implementing a Custom Download Manager?
Asynchronous pluggable protocols enable developers to create pluggable protocol handlers, MIME filters, and namespace handlers?
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A easy method is using UrlDownloadToFile()
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How to add Common Controls 6.0 to DLL / ATL ?
I don't have the source code of the EXE, I'm writing only the DLL linked to it.
If I put this line in the stdafx.h of the DLL it doesn't work:
#pragma comment(linker,"/manifestdependency:\"type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' processorArchitecture='x86' publicKeyToken='6595b64144ccf1df' language='*'\"")
InitCommonControls(); / InitCommonControlsEx();
is not working neither,
I need Common Controls 6.0 to show my tooltips controls and they work only with the manifestdependency line at the exe file / or manifest file to exe
Thanks for anyone who can help,
Mithrill
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If you are allowed, then try modifying the manifest inside the executable, -as far as i know- it is stored as resource inside the executable and you can modify resources in the binary. Try using UpdateResource[^] or google for applications that can do this.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<
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Maybe there is a way to do that with
LoadLibrary(comctl32.dll)
GetProcAddress ???
In some kind of dynamic way ?
There must be a way
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I wonder, does the exe load comctl32.dll but calls InitCommonControls[^] and not InitCommonControlsEx[^] and would it help if it were to call the Ex version? You could try hooking the InitCommonControls API method and call the Ex version instead, i wonder if that would work.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<
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I've found it easier to create a .manifest or .xml file in the res folder, and then add the apropriate entry to the .rc file.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Some people are making such thorough preparation for rainy days that they aren't enjoying today's sunshine." - William Feather
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You cannot do this in a DLL, only in the original executable. The #pragma is meaningless in a DLL because it only gets loaded on demand and is not allowed to conflict with the settings of the main executable. You will either need to get hold of the source or object code of your executable and rebuild it or live with the problem.
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But there is no way of loading Common Controls from DLL ??
Maybe forcing the InitcommonControlsEx to load the 6.0 version like the pragma/manifest does ?
Mithrill
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Not unless the EXE program calls a function in the DLL immediately on startup. You are trying to alter the conditions and environment of an application without the application itself being involved, and I don't think that is viable. As I said before, you need to get the source code of the application and change that.
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It sounds to me like you should be looking into "XP Style Hacker"
I've used this program dozens of times to make old programs look more modern. It creates a manifest file in the same folder as the executable. No need to modify the original, as windows loads the manifest file, PROVIDED it has a name in the correct format. I seem to remember this as being "exeFilename.exe.manifest".
The tool's free to download and use, I reckon it's just what you're looking for.
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I can't change the exe cause of company restrictions, I have only the DLL programming and I don't
Distribute the EXE, I Just write a DLL and deliver it to the other guys abroad.
I work in a big firm, I can't change the EXE 
Mithrill
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I had no idea of the size of the company you work for (& no more interest, to be honest)
I'm not advocating the changing of any exe file.. If you take the time to actually look at the tool "XP Style Hacker", you'll come to understand that so long as you have a copy of the EXE, it will create the manifest file for you. You can then distribute the manifest file with the rest of your code. Provided the manifest file is put into the same folder as the EXE file, it'll just work.
So please, do yourself a favour and actually try the tool...
EDIT: And please re-read my last post. It seems your reading and comprehension skills are a little depleted today. I said in my last post that there was no need to change the exe.... 
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mithrill wrote: I work in a big firm, I can't change the EXE
Then you need to explain to your boss that what you are being asked to do is not technically feasible, and he needs to go back to the people responsible for the EXE and tell them they will have to change their application.
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Hi!
Is it possible to code classes, polymorphism and every other
Object oriented concepts in C also?
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There's an app article for that: Polymorphism in C[^]
"Real men drive manual transmission" - Rajesh.
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Thank you Sir! for the quick reply. Can you tell me what is the difference between C & C++ then?
Why C++ if C could do all things that C++ can do? Please give me some explanation.
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