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consider varB has only a destination pointer. So when you change its address, varA itself does not change. I think you need a reference variable. This acts like an alias of the original variable itself.
Another thing, the original sample code has a fundamental bug. This involves the temp local variable. The moment your function returns, the variable goes out of scope and the pointer value set to varB will immediately become invalid. You can check this by tracing through the code.
I Dream of Absolute Zero
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Friend i want to detect whether certain path or directory exists or not ? For example i like to know that following path is a valid path:
c:\Program Files\BLAH\BLAH
Please tell me how can i achieve the taks of finding out whether the path is correct OR how can i detect whether some directory exists or not ??
BTW, according to MSDN we can check the existance of direcory using CreateFile() with FILE_FLAG_BACKUP_SEMANTICS flag. But it is not supported in Windows 98.
Imtiaz
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bool dirExists
(CString strDirectory)
{
TCHAR* fullPath = _tfullpath (NULL, strDirectory, 0);
if (fullPath == NULL)
return (false);
TCHAR szCurrDir [_MAX_PATH];
_tgetcwd (szCurrDir, _MAX_PATH - 1);
long nStatus = _tchdir (fullPath);
_tchdir (szCurrDir);
free (fullPath);
if (nStatus == 0)
return (true);
return (false);
}/ravi
My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com
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Try [PathFileExists] api
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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Hi, all
I added an ActiveX controll of the Window Media Player to my MFC program. I can successfully open the About Box of the Media Play by using its member variable: m_Ctrl.AboutBox();
However, I can't load a wave file and playback the file. When it executed: m_Ctrl.play(), an error message box came up without providing any error message.
Does anyone know the steps of controlling Window Media Player? And also the problem I had?
Thanks for your help !
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I want to add code to a program to force it to run on startup based on a checkbox value. Is there a way to do this without hard coding the registry path (HKEY_......CurrentVersion\Run)? I guess I'm looking for a function that either returns that registry path or a function that automatically adds a value to the registry.
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Just hard code the value, it is not going anywhere.
Use a registry function from CRegKey to get the work done, or one of the registry classes from this website.
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Add this function to your program
void CYourDlg::somefunction()
{
CRegKey key;
LONG status=key.Open(HKEY_LOCAL_MACHINE,"Software\\Microsoft\\Windows\\CurrentVersion\\Run");
if(status==ERROR_SUCCESS)
{
key.SetValue("c:\\...youprogrampath.exe","ProgramName");
key.Close();
}else //some error message ;
}
m0n0
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Hi,
I have several (6)points(x,y) and having troubles smoothing the curves of these points. I tried using the PolyBezier function without any luck. I would like to provide the points, and the function to draw the smoothed curves that is very similar to what Excel does. Any ideas?
Thanks
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Ok... I think you are going down the right path with PolyBezier. But you have to think a bit about how beziers work. There's an article here[^] on the subject (ignore the code at the bottom - windows implements that for you!). So each point on the polygon has two bezier handles associated with it... one for the next line segment, and on for the previous. Now what I think Excel does is choose the positions of those bezier handles for you automatically. The two points are in a smooth arrangement - so the the polygon point, and the two bezier handles form a straight line. The distance between the handle and polygon point is chosen in proportion to the length of the line segmet it applies to. With me so far?
Additionally the line formed by the polygon point and the two bezier handles is angled in way to be sort of tangential to the polygons. It seems to take an average between the angle of the first and last segments (whether weigthed by length I'm not sure).
so I think you need to do something like this:
void DrawSmoothedPolygon(HDC dc, POINT *pointlist, int pointcount)
{
const float curvyness = 0.1f;
float prevseglength, nextseglength;
long dx, dy;
long leapfrogdx, leapfrogdy;
ASSERT(pointlist != NULL);
ASSERT(pointcount >= 3);
POINT *curvepoints = new POINT[pointcount * 3 + 1];
curvepoints[0] = pointlist[i];
curvepoints[1] = pointlist[i];
curvepoints[pointcount * 3 + 1] = pointlist[pointcount];
curvepoints[pointcount * 3] = pointlist[pointcount];
dx = (curvepoints[1].x - curvepoints[0].x);
dy = (curvepoints[1].y - curvepoints[0].y);
nextseglength = sqrt(dx*dx + dy*dy);
for(int i = 1; i < pointcount - 1; i++)
{
leapfrogdx = (curvepoints[i-1].x - curvepoints[i+1].x);
leapfrogdy = (curvepoints[i-1].y - curvepoints[i+1].y);
preveglength = nextseglength;
dx = (curvepoints[i+1].x - curvepoints[i].x);
dy = (curvepoints[i+1].y - curvepoints[i].y);
nextseglength = sqrt(pointlist[i].x * pointlist[i].x + pointlist[i].y * pointlist[i].y);
curvepoints[i * 3] = pointlist[i];
curvepoints[i * 3 + 1].x = pointlist[i].x + leapfrogdx / (nextseglength / curvyness);
curvepoints[i * 3 + 1].y = pointlist[i].y + leapfrogdy / (nextseglength / curvyness);
curvepoints[i * 3 - 1].x = pointlist[i].x - leapfrogdx / (prevseglength / curvyness);
curvepoints[i * 3 - 1].y = pointlist[i].y - leapfrogdy / (prevseglength / curvyness);
}
PolyBezier(dc, curvepoints, pointcount * 3 + 1);
delete[] curvepoints;
}Now I'm not sure how well this will work. But it may give you some ideas to start with. Also it doesn't deal with closed curves... I'll leave you to figure those out 
Joel Holdsworth
Wanna give me a job this summer?
Check out my online CV and project history[^] - now available in MSWord format![^]
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I have a class exported from a DLL which has a member of type _ConnectionPtr. I am importing the ADO library in the DLL as follows:
#import "msado15.dll" no_namespace named_guids rename("EOF", "adoEOF")
The _ConnectionPtr is defined using the _com_ptr_t<..> template in the ADO library, and since the template definition is not exported I get the above warning when compiling.
If I had a member of a simpler template type in the class, for e.g.:
MyTemplate<int> my_member;
..it would just be a matter of exporting the 'instantiated' template definition in the class definition like this:
<br />
class __declspec(dllexport) CParameters<br />
{<br />
public: ....<br />
protected: ....<br />
<br />
template class __declspec(dllexport) MyTemplate<int>;<br />
MyTemplate<int> my_param;<br />
};<br />
However, i am at a loss on how to proceed with the _ConnectionPtr template definition. The warning i get from the compiler is as follows (m_pConn is the member, CParameters is the exported class):
warning C4251: 'm_pConn' : class '_com_ptr_t<class _com_IIID<struct _Connection,&struct __s_GUID _GUID_00000550_0000_0010_8000_00aa006d2ea4> >' needs to have dll-interface to be used b<br />
y clients of class 'CParameters'
Otherwise, the thing compiles ok and the m_pConn is initialised properly as a connection, but i would like to iron out these warnings.
Any ideas?
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It's not very useful to export classes with templates!
You can fix the problem by creating a static library instead of a DLL.
The compiler tells you that an application that wants to use the DLL has to know the definition of _com_ptr_t<class _com_iiid<struct="" _connection,&struct="" __s_guid="" _guid_00000550_0000_0010_8000_00aa006d2ea4=""> > to be able to use the class. A static library would be the best solution.
Don't try it, just do it! 
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Hi Alex...thanks for replying.
The thing is this: the dll i am writing will be used by a service. If i link it statically, i would have to re-compile the service each time i change something in the dll, right? It's something i would like to avoid.
The problem lies in the ADO template which i am using in my dll. If it was my template i would have found another way, however i'm not that flexible with ADO.
Further feedback is welcome...!
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Yes...saw that...but can't find how to use the same approach for the _ConnectionPtr for ADO...the declaration is way too complex.
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What about using the pragma warning??
Papa
while (TRUE)
Papa.WillLove ( Bebe ) ;
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Yes ok, it will work...but it's not much of a solution now, is it? 
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My program needs to access shares on a different computer but as a different user than the one running the application. If anybody can point me to the basic API functions to do this, it will be greatly appreciated.
The basic function I guess would be to stablish a connection with credentials programatically. In any case I just need a pointer to the documentation.
Thank you
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Something like this:
LogonUserEx() -> ImpersonateLoggedOnUser() -> Access The Shares -> RevertToSelf()
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You can use NetUseAdd() for this.
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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Thank you! NetUseAdd() is exactly what I was looking for 
The one for the local computer is interesting too, good to know it's also possible.
Thank you both.
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hi
I have problem in sorting the array alphbetically.
I have the names of students only first names.I have the function which works but doesn't gives the consistent result as it should .
So can any one help in getting the problem to be solved
my array declaration is char *names[100];
Best REgards
Jhon
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If you post what you've come up with so far, I'm sure someone here will be able to solve the problem.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
Want a Boost forum in Code Project? Vote here[^]!
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