C / C++ / MFC

27-Dec-08 22:57

This is the Function declaration :
int MyClass::Send (MY_STRUCT *cStruct,
void *Para1, void *Para2,
void *Para3, void *Para4, void *Para5, void *Para6)
{
......
}

But when this function is executed ,why Para1...Para6 do not appear in the function?

MY_STRUCT Querries
Send(&Querries)

Thanks

Code-o-mat27-Dec-08 23:35

27-Dec-08 23:35

what do you mean, "do not appear"?

> The problem with computers is that they do what you tell them to do and not what you want them to do. <

dec8227-Dec-08 23:44

Re: execute a function? [modified]

27-Dec-08 23:44

i mean why the number of parameters in the declaration and exectution is diffrent? any way, cause i don't understand why type for Para1, ...Para6 is void?
Thanks

Code-o-mat28-Dec-08 0:24

28-Dec-08 0:24

I think i understand what you mean. First, what you have shown as declaration seems to be more like the definition of the method. I think what causes you confusement is that at the definition you see that the method takes 7 parameters and where it is called, only one is specified. I supose that the DECLARATION of the method either gives default values of the parameters, or there is another version of this function with only one parameter. So something like:

class MyClass
{
  ...
  int Send(MY_STRUCT *cStruct, void *Para1=NULL, void *Para2=NULL, void *Para3=NULL, 
                               void *Para4=NULL, void *Para5=NULL, void *Para6=NULL);
  ...
}

class MyClass
{
  ...
  int Send(MY_STRUCT *cStruct, void *Para1, void *Para2, void *Para3, 
                               void *Para4, void *Para5, void *Para6);
  int Send(MY_STRUCT *cStruct);
  ...
}

For the void thing, the type of those parameters is not void but void*, void pointer. This basicly means it is a non-typized pointer.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <

modified on Sunday, December 28, 2008 6:45 AM

dec8228-Dec-08 3:46

28-Dec-08 3:46

what the purpose of using void pointer?

Code-o-mat28-Dec-08 3:56

28-Dec-08 3:56

See ^CPallini's post[^]. Void pointers are "generic", if you make an "int pointer" (int *) you expect it to contain the address of an integer, if you make a "double pointer" (double *), you expect it to point at a double in memory, and so on, a void pointer can point to anything and it is "up to the context" what is done with it.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <

Hamid_RT28-Dec-08 0:03

Hamid_RT

28-Dec-08 0:03

Your code with this on the header file

int Send (MY_STRUCT *cStruct,
void *Para1=NULL, void *Para2=NULL,
void *Para3=NULL, void *Para4=NULL, void *Para5=NULL, void *Para6=NULL);
or like this. Wink | ;)

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

CPallini28-Dec-08 2:45

CPallini

28-Dec-08 2:45

See [^].

A void pointer (void *) can point to anything (usually additional info about the pointed memory data type is given by a well-know argument, in your case maybe the first one).
Smile | :)

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]

string and char?

dec8227-Dec-08 22:36

SetWindowRgn For Text Or Label

27-Dec-08 22:36

what the different between string and char?
does 'char' mean character? why we have 'unsigned char' type?
Thanks

Re: string and char?

Hamid_RT28-Dec-08 0:08

Hamid_RT

28-Dec-08 0:08

Character types in C and C++[^],String (C++)[^].

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Re: string and char?

CPallini28-Dec-08 2:40

CPallini

28-Dec-08 2:40

Generally, with string we mean a sequence (i.e. one or more) of characters.
In C language, char is a data type (corrensponding to a 8-bit signed integer, i.e. ranging from -128 to 127, while an unsigned char is a 8-bit unsigned integer, i.e. ranging from 0 to 255), a string is, by convention, a sequence of chars zero terminated, for instance:

//CHAR VARIABLES
char c1 = 'A';
char c2 = 13;
char c3 = -20;

// UNSIGNED CHAR VARIABLES
unsigned char uc1 = 10;
unsigned char uc2 = 'A';
unsigned char uc3 = 250;

// STRINGS
char s1[]= { 'H', 'e', 'l', 'l', 'o', '\0'};
char s2[]= "Hello"; //Shorthand form of the above

yytg27-Dec-08 20:23

27-Dec-08 20:23

There is a lot of samples for RGN's for bitmaps but I need to create a RGN for Text with a font and size.
How can I do it?

thanks in advance

Hamid_RT28-Dec-08 0:08

Hamid_RT

28-Dec-08 0:08

Can you more explain,please? Wink | ;)

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

yytg28-Dec-08 2:04

28-Dec-08 2:04

I want to display text on the screen in such a way so the user will see only the text (Not the window).
The RGN is made to disable coloring outside of specific places in the window.
The effect of it is so you can make windows in a shape you design as so
http://www.codeproject.com/KB/GDI/coolrgn.aspx[^].
How do I do the same effect on text?

Code-o-mat28-Dec-08 2:17

28-Dec-08 2:17

Do you mean you wish to create a region with the shape of text? If so, try this, am not sure if it works but it is worth a try:
1. Create your font and select into a DC (a memory DC should work)
2. Use BeginPath to begin defining a path
3. Use TextOut or DrawText or such to display the text
4. Use CreateFromPath[^] to create a region.

It is possible that it only works with vector-based fonts.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <

yytg28-Dec-08 6:53

28-Dec-08 6:53

Thanks for helping
The function don't work with all fonts so I did this

SetRgn(CString str)
{
	CRect r;GetClientRect(&r);
	CMemoryDC dc(GetDC(),r);
	CFont font;font.CreatePointFont(120,L"Arial",0,true);
	COLORREF bgColor=dc.GetBkColor();
	dc.FillSolidRect(r,bgColor);

	dc.SelectFont(font);
	dc.TextOut(0,0,str);

	CRgn rgn,tRgn;rgn.CreateRectRgn(0,0,0,0);
	for (int x=r.left;x<r.right;x++)>
	{
		for (int y=r.top;y<r.bottom;y++)>
		{
			if(!(!tRgn))tRgn.DeleteObject();
			COLORREF c=dc.GetPixel(x,y);
			if(c!=bgColor)
			{
				tRgn.CreateRectRgn(x,y,x+1,y+1);
				rgn.CombineRgn(rgn,tRgn,RGN_OR);
			}
			
		}
	}
	SetWindowRgn(rgn);
}

Code-o-mat28-Dec-08 9:39

Re: SetWindowRgn For Text Or Label [modified]

28-Dec-08 9:39

I supose it really only works for vector-fonts since a raster-font probably has nothing to put into a path...Anyways, isn't that solution a bit slow?

> The problem with computers is that they do what you tell them to do and not what you want them to do. <

yytg29-Dec-08 3:01