Re: string and char? - C / C++ / MFC Discussion Boards

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

Re: execute a function?

dec8228-Dec-08 3:46

dec82

28-Dec-08 3:46

what the purpose of using void pointer?

Re: execute a function?

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

Code-o-mat

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. <

Re: execute a function?

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 )

Re: execute a function?

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

dec82

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

SetWindowRgn For Text Or Label

yytg27-Dec-08 20:23

yytg

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

Re: SetWindowRgn For Text Or Label

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 )

Re: SetWindowRgn For Text Or Label

yytg28-Dec-08 2:04

yytg

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?

Re: SetWindowRgn For Text Or Label

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

Code-o-mat

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. <

Re: SetWindowRgn For Text Or Label

yytg28-Dec-08 6:53

yytg

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);
}

Re: SetWindowRgn For Text Or Label

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

Code-o-mat

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. <

Re: SetWindowRgn For Text Or Label [modified]

yytg29-Dec-08 3:01

yytg

29-Dec-08 3:01

I did a test in debug mode with breakpoints...(not the best way to check)
1000*1000=1,000,000 loop
It was only 5 sec.
a normal textout will not export so much as so.

Update...

	CSize sizeText;dc.GetTextExtent(str,str.GetLength(),&sizeText);
	for (int x=r.left;x<sizetext.cx;x++)>
	{
		for (int y=r.top;y<sizetext.cy;y++)>
....

modified on Monday, December 29, 2008 9:34 AM

Why fclose is so slow and what is its internal implematation.

Vishal Kumar Soni27-Dec-08 10:27

Vishal Kumar Soni

27-Dec-08 10:27

On some files fclose is taking long time to close the file.Can someone please tell that in which condtion it can take time to close and how it is internaly implemented?

Thanks in advacnce.
Regards,
Vishal

Re: Why fclose is so slow and what is its internal implematation.

Richard Andrew x6427-Dec-08 11:55

Richard Andrew x64

27-Dec-08 11:55

Try calling flush() to flush all writes to the file before calling fclose().

This may reveal that the cause of the slowness is the buffered writes.

Re: Why fclose is so slow and what is its internal implematation. [modified]

Vishal Kumar Soni27-Dec-08 21:12

Vishal Kumar Soni

27-Dec-08 21:12

Thanks Richard.
I have tried fflush before fclose.fflush returns immidately but fclose is taking time.time for closing the files get increased with increase in file size. with 100MB it is 30 sec.With 200MB,it is 1 min and 300MB it is 2min and so on.It is happening with one type of files(.dat files) only.I tried by closing some other file at same path with same code and this file is closed immidately.I have tried everything but I am not able to find the reason.Please give some other sugestion,I can try.

Thanks
Vishal

modified on Sunday, December 28, 2008 4:18 AM

Re: Why fclose is so slow and what is its internal implematation.

Luc Pattyn28-Dec-08 2:16

Luc Pattyn

28-Dec-08 2:16

Hi,

is there anything special about your file? e.g. is it on another PC, in a special folder, ...?
does it need some post-processing, like compression, encryption, ...?

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Fixturized forever. Confused | :confused:

Re: Why fclose is so slow and what is its internal implematation.

Vishal Kumar Soni28-Dec-08 5:40

Vishal Kumar Soni

28-Dec-08 5:40

Thanks Luc.
There is nothing special about this file.It is just *.dat file in which logging message are written.It is not in another PC and it is not in special folder.
To confirm this,I have also tried by putting some other file with same size on this folder and rename in to culprit file name but this file get closed immidately.
After completion of this file(on day change new file is created), it is processed by some other modules to create the reports.

Thanks,
vish

Re: Why fclose is so slow and what is its internal implematation.

Mark Salsbery28-Dec-08 4:59

Mark Salsbery

28-Dec-08 4:59

The source code comes with Visual Studio.

Why not step into the fclose() code with the debugger and see what's
happening?

Mark

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

Re: Why fclose is so slow and what is its internal implematation.

Vishal Kumar Soni28-Dec-08 5:56

Vishal Kumar Soni

28-Dec-08 5:56

Thanks Mark.
I tried to debug "fclose" on my m/c.It is not going inside of fclose.
I am not able to see its code also.I was assuming that only header files comes with visual studio.

If I can see its code then it would be great help.Could you please tell that at which location these
source files are?
Althogh this problem is not reproducible on my local m/c.It is happening on live system only.
Even then,I can see code and put some OutputDebug strings to see where it is taking time.

Please tell that how can I step in to fclose?

Thanks,
Vishal

Re: Why fclose is so slow and what is its internal implematation.

Mark Salsbery28-Dec-08 6:26

Mark Salsbery

28-Dec-08 6:26

What version of Visual Studio are you using?

I see fclose() implemented in the file C:\Program Files\Microsoft Visual Studio 9.0\VC\crt\src\fclose.c
on Visual Studio 2008.

I would guess the delay is happening when the buffered contents are flushed (i.e. actually written)
to disk. You can check by opening the file with the commit flag (c) and calling fflush()
(without that flag, fflush() returns immediately).

Mark

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

Re: Why fclose is so slow and what is its internal implematation.

Vishal Kumar Soni28-Dec-08 8:10

Vishal Kumar Soni

28-Dec-08 8:10

Earlier I had doubt related to fflush or some other factor.To know this first I tried by calling fflush just before fclose.It does not make any difference.

Then in second test ,I tried by just open and close the file.Nothing in between these two.
even in this case it was taking time.

I wil try by giving "c" in file open mode.Now I opening the file by "a+",I will change it by "ca+".

Can I also put some logging message in fclose it and recompileit lirary?

Thanks,
Vishal

Re: Why fclose is so slow and what is its internal implematation.

Mark Salsbery28-Dec-08 8:16

Mark Salsbery

28-Dec-08 8:16

Vishal Kumar Soni wrote:
first I tried by calling fflush just before fclose.It does not make any difference.

Correct. fflush() doesn't flush without the commit flag.

Vishal Kumar Soni wrote:
Can I also put some logging message in fclose it and recompileit lirary?

Much easier to use the debug CRT library and step into it with the debugger.
Surely if you have the CRT source code to do a rebuild, you should be able to
step into the debug build of the library Smile | :)

Also, if you don't like the performance of fopen/fclose file I/O, there are other options...
like direct Win32 calls.

If you don't want data to be buffered, you'll need to use unbuffered I/O Smile | :)

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

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