C / C++ / MFC Discussion Boards

Paul M Watt16-Feb-02 7:05

16-Feb-02 7:05

If you are not using MFC, then you will be interested in memory mapped files.

1. open your file with CreateFile.

2. Call CreateFileMapping with the handle that you received from CreateFile. You will also need to specify things like the size of the file that you want to read into memory and access that you would like to have to the file.

3. Call MapViewOfFile, this function will return a pointer to you that you can treat exactly like memory.

Depending on the settings that you choose, when you close the file mapping, all of the memory that you have changed will already be written to Disk.

In one of the other responses to your question, CMemFile encapsulates this behavios, but you will have to use MFC.

having a ansistring = "

Steven Richardson16-Feb-02 2:48

Steven Richardson

16-Feb-02 2:48

i need Tmp = "; but i get an error, is there a way of having Tmp = "

Re: having a ansistring = "

Joaquín M López Muñoz16-Feb-02 3:01

Joaquín M López Muñoz

16-Feb-02 3:01

If I understood you right, Tmp = "\""; is what you're after.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: having a ansistring = "

Steven Richardson16-Feb-02 3:10

Steven Richardson

16-Feb-02 3:10

thanks worked great but do you know what to do for a return? Tmp = " go on to a new line? "

Re: having a ansistring = "

Joaquín M López Muñoz16-Feb-02 3:28

Joaquín M López Muñoz

16-Feb-02 3:28

\n new line
\t horizontal tab
\b backspace
\f form feed
\a alert or bell
\r carriage return
\v vertical tab
\\ backslash
\' single quote
\" double quote

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Radio Buttons

16-Feb-02 1:51

I've a dialog box with radio buttons and i'd like to know how to preselct the radio buttons.
The resource is called ID_DIALOG and was created using the Resource editor the radio buttons added from the Controls Menu and is created in a class derived from CDialog!
Can u help me cheers - Jason

Re: Radio Buttons

Mazdak16-Feb-02 1:58

Mazdak

16-Feb-02 1:58

put this in your OnInitDialog after you define controller:

m_myradio.SetCheck(true);

Mazy

Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without

Re: Radio Buttons

16-Feb-02 2:34

Another way of doing this is assign the radio button in a group and then for the first radio button make a int variable from the Class Wizard. Assigning values 0, 1, 2 ... sets the different check boxes. Assign a value in the initdialog box or the constructor.

Farsi strings problem !!!

Hadi Rezaee16-Feb-02 1:30

Hadi Rezaee

16-Feb-02 1:30

Hi all,
I added new Language to my Win2000 OS ...
It is Farsi language ...
I wanna change my Windows Titlebars and Buttons labels from English U.S. to Farsi strings in my program.
So, I changed my Window Language to Neutral in Resource Tab ...
But when i run the program, i can only see some strange ANSI characters in Titlebars and button labels !!!

NOTICE: I can not write the Farsi strings in VC++ Editor directly !!!

How can i solve it ??? (Please help me ...)

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Re: Farsi strings problem !!!

Mazdak16-Feb-02 2:04

Mazdak

16-Feb-02 2:04

yes Hadi,this is the same problem that I had it too,it seems we can't
use farsi in our application in this way,I'm sorry to say that I used it in
Dephi in this way. Frown | :(

I think the only way is we have to buy farsi edition of VC,Do you know where can you buy it? Smile | :)

Mazy

Don't Marry a Person You Can Live With...
Marry Someone You Can Not Live Without

Opening more than 509 files using VC++ 6.0 SP5

16-Feb-02 1:01

Hi,

I need some pieces of advise regarding the following problem:

I would like to create a program than open safely more than 509 files on Win NT/2K plateforms.

Effectively, Windows NT allows one process to open 2048 files, and WIndows 2K allows even more than 16000 files.

However, an application builded with VC++ 6.0 seems limited to 509 opened files.

I figured out that 509 + 3 (stdin/stdout/stderr) = 512, which is the values of the _NSTREAM_ macro within the CRT source code.

Therefore, I tried to compile the CRT after changing this value to 1024. Bingo ! I could effectively opened 1024 - 3 = 1021 files.

BUT MY APPLICATION CRASHED BECAUSE OF getchar() !!

I guess that my compiled version of the CRT is not exactly the same as the real MSVCRT.DLL.

So, I would appreciate if someone can confirm what to do exactly to open more than 509 files uisng VC++ 6.0

Thanks for any help you can provide.

Regards.

Hassan
Paris, FRANCE

Re: Opening more than 509 files using VC++ 6.0 SP5

Nish Nishant16-Feb-02 1:09

Nish Nishant

16-Feb-02 1:09

It might be a good idea to optimize your design a little bit [nothing to do with your nick of course] to avoid having to open 500 plus files at the same time.

Nish

Nish was here, now Nish has gone;
He left his soul, to turn you on;
Those who knew Nish, knew him well;
Those who didn't, can go to hell.

I like to Jig | [Dance]

on the Code Project

Sonork ID 100.9786 voidmain
www.busterboy.org

Re: Opening more than 509 files using VC++ 6.0 SP5

16-Feb-02 4:02

Hi Nish,

Thanks for answering.

Yes you're right, trying to open so many files is not a good idea.

However, it is not my design.

To tell the full story, I have to find a workaround for some application
which I don't have the source code.

This application is opening files all the day using incoming data from the outside.
The basic idea was to make it runs all the day. Then at "midnight", I stop this application, I do a merge on all files created during the day, and I restart the application.

Unfortunately, the incoming dataflow is so high, that the maximum number of file handle is not enough. Also, there is no way to stop the application at noon for instance because this application must run during all business day.

Now, if I can find a way to "patch" msvcrt to open at least 1200 files, then I can use this custom MSVCRT.DLL and make the application run as planned.

Any better idea is welcome.

Regards.

Hassan

Re: Opening more than 509 files using VC++ 6.0 SP5

Rick York16-Feb-02 6:29

Rick York

16-Feb-02 6:29

There are articles on this site that relate to injecting your code in place of other code. You could use dumpbin and figure out exactly what imports your "other" app is using and make replacements for those functions with your modified CRT library.

Good Luck.

Dont know the meaning of this constants.

tppradeep1815-Feb-02 20:51

tppradeep18

15-Feb-02 20:51

I am new to the curious world of MFC. I used the appwizard that created a resource.h file having the following content. Could someone please tell me what is IDM_ABOUTBOX and IDS_ABOUTBOX here. IDD_ABOUTBOX is the default About Boxs' ID in resource Editor. I am confused about the latter two Constants. Please hold my hand !!!

#define IDR_MAINFRAME 128
#define IDM_ABOUTBOX 0x0010
#define IDD_ABOUTBOX 100
#define IDS_ABOUTBOX 101
#define IDD_DIALOG_DIALOG 102

Dont argue with a fool, audience cannot find the difference.

Re: Dont know the meaning of this constants.

Nish Nishant15-Feb-02 21:37

Nish Nishant

15-Feb-02 21:37

Those constants are resource identifiers.

Nish

Nish was here, now Nish has gone;
He left his soul, to turn you on;
Those who knew Nish, knew him well;
Those who didn't, can go to hell.

I like to Jig | [Dance]

on the Code Project

Sonork ID 100.9786 voidmain
www.busterboy.org

Re: Dont know the meaning of this constants.

alex.barylski15-Feb-02 22:25

alex.barylski

15-Feb-02 22:25

IDM prefix I would think would be the resource identifier thats associated with the about menu appended to your dialogs system menu. IDS prefix is for the string table reosurce.

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

where is the problem?

15-Feb-02 19:59

void Investors:: addInvestor(Investor& in)
{
Investor* temp = new Investor[numOfInvestors+1]; //create a new investor array of size of prevArray+1
if (investorsList == NULL) //check if there is something in the array
{
investorsList = temp; //save temp in investorsList
investorsList[0] = in; //fill the first element with the investor that you want to add
} //to your list
else //else if the investorsList is not NULL
{
for (int i = 0; i< numOfInvestors; i++) //in this loop you start copying the elements of the prevlist in
{ //the new temp list
temp[i] = investorsList[i];
cout <

Re: where is the problem?

15-Feb-02 21:22

It doesn't seem to have pasted correctly down the bottom so I'm not sure exactly what's going on, some possibilities:
. you seem to be using investorsList after you've deleted it.
. investorsList=temp; //shouldn't this be done somewhere?
. numOfInvestors++ seems to be done twice
good luck

Re: where is the problem?

alex.barylski15-Feb-02 22:22

alex.barylski

15-Feb-02 22:22

It's hard to read code that isn't formatted correctly also, so perhaps use the pre, tag. it preserves your orignal whitespace so tabs actually indent.

if(a==b)
AfxMessageBox("Example of pre tag");

is instead

if(a==b)
    AfxMessageBox("Example of pre tag");

Remember to close your tags too!

Cheers!

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: where is the problem?

16-Feb-02 1:34

void Investors:: addInvestor(Investor& in)
{ 
    Investor* temp = new Investor[numOfInvestors+1];  //create a new investor array of size of prevArray+1
	if (investorsList == NULL)                        //check if there is something in the array	
	{
		investorsList = temp;                         //save temp in investorsList
		investorsList[0] = in;                        //fill the first element with the investor that you want to add 
	}                                                 //to your list
	else                                              //else if the investorsList is not NULL
	{
		for (int i = 0; i< numOfInvestors; i++)       //in this loop you start copying the elements of the prevlist in
		{                                             //the new temp list
			temp[i] = investorsList[i];	
			cout <<investorslist[i]<<endl;
 }
="" temp[numofinvestors]="in;" copy="" the="" new="" element="" in="" last="" position
="" numofinvestors++;="" increment="" numofinvestors
="" delete="" []="" investorslist;="" old="" list
="" for(="" i="0;" i<numofinvestors;="" i++)
="" {
="" investorslist[i]="temp[i];" 
="" insertionsort(investorslist,="" numofinvestors);
="" investorslist[numofinvestors];="" numofinvestors++;
}="" 
<\pre="">

Re: where is the problem?

alex.barylski16-Feb-02 12:01

alex.barylski

16-Feb-02 12:01

Your missing a few brackets and your syntax is a little off.

//Tip: class members should be prefixed with m_ so others can tell what non locals are.
//NumOfInvestors, investorList i'll assume are class members

void Investors::addInvestor(Investor& in)
{     
	Notice your new is created
	Investor* temp = new Investor[numOfInvestors+1];  
	
	//create a new investor array of size prevArray+1	
	if (investorsList == NULL) 
	{		
		investorsList = temp;                         
		
		//save temp in investorsList		
		investorsList[0] = in;                        
	}   
	else   
	{		
		for (int i = 0; i< numOfInvestors; i++)  //in this loop you start copying the elements of the prevlist in		
		{                                             
			//the new temp list			
			temp[i] = investorsList[i];				
			cout <<investorsList[i]<<endl;		
		}        
			temp[numOfInvestors] = in;  //copy the new element in the last position    	
			numOfInvestors++;           //increment the numOfInvestors    	
			
			Notice your new is deleted, but what happens if else isn't executed
			delete [] investorsList;    //delete old list    	
		
			//This isn't going to make sense to the compiler
			
			for(i = 0; i				//Your syntax here was off a little
			{
				investorsList[i] = temp[i]; 		
			}	
			
			insertionSort(investorsList, numOfInvestors);	
			
			investorsList[numOfInvestors];               	
			numOfInvestors++;
	} 
	delete should go here unless your if constructs return early
}

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: where is the problem?

16-Feb-02 12:21

for(i = 0; i //Your syntax here was off a little { investorsList[i] = temp[i]; }

I could not copy and paste the right code for some reason.
it kept truncating that part of the for statement that you are pointing it to reight above i will try to copy for the last time!
hope it works this time!

void Investors:: addInvestor(Investor& in)
{ 
    Investor* temp = new Investor[numOfInvestors+1];  //create a new investor array of size of prevArray+1
	if (investorsList == NULL)                        //check if there is something in the array	
	{
		investorsList = temp;                         //save temp in investorsList
		investorsList[0] = in;                        //fill the first element with the investor that you want to add 
	}                                                 //to your list
	else                                              //else if the investorsList is not NULL
	{
		for (int i = 0; i< numOfInvestors; i++)       //in this loop you start copying the elements of the prevlist in
		{                                             //the new temp list
			temp[i] = investorsList[i];	
			cout <<investorslist[i]<<endl;
 }
="" temp[numofinvestors]="in;" copy="" the="" new="" element="" in="" last="" position
="" numofinvestors++;="" increment="" numofinvestors
="" delete="" []="" investorslist;="" old="" list
="" for(="" i="0;" i<numofinvestors;="" i++)
="" {
="" investorslist[i]="temp[i];" 
="" insertionsort(investorslist,="" numofinvestors);
="" investorslist[numofinvestors];="" numofinvestors++;
}="" <\pre="">

this is the right code

16-Feb-02 12:26

void Investors:: addInvestor(Investor& in)
{ 
    Investor* temp = new Investor[numOfInvestors+1];  //create a new investor array of size of prevArray+1
	if (investorsList == NULL)                        //check if there is something in the array	
	{
		investorsList = temp;                         //save temp in investorsList
		investorsList[0] = in;                        //fill the first element with the investor that you want to add 
	}                                                 //to your list
	else                                              //else if the investorsList is not NULL
	{
		for (int i = 0; i< numOfInvestors; i++)       //in this loop you start copying the elements of the prevlist in
		{                                             //the new temp list
			temp[i] = investorsList[i];	
			cout <<investorslist[i]<<endl;
 }
="" temp[numofinvestors]="in;" copy="" the="" new="" element="" in="" last="" position
="" numofinvestors++;="" increment="" numofinvestors
="" delete="" []="" investorslist;="" old="" list
="" for(="" i="0;" i<="" numofinvestors;="" i++)
="" {
="" investorslist[i]="temp[i];" 
="" insertionsort(investorslist,="" numofinvestors);
="" investorslist[numofinvestors];="" numofinvestors++;
}="" <\pre="">

Re: this is the right code

16-Feb-02 12:27

void Investors:: addInvestor(Investor& in)
{ 
    Investor* temp = new Investor[numOfInvestors+1];  //create a new investor array of size of prevArray+1
	if (investorsList == NULL)                        //check if there is something in the array	
	{
		investorsList = temp;                         //save temp in investorsList
		investorsList[0] = in;                        //fill the first element with the investor that you want to add 
	}                                                 //to your list
	else                                              //else if the investorsList is not NULL
	{
		for (int i = 0; i< numOfInvestors; i++)       //in this loop you start copying the elements of the prevlist in
		{                                             //the new temp list
			temp[i] = investorsList[i];	
			cout <<investorslist[i]<<endl;
 }
="" temp[numofinvestors]="in;" copy="" the="" new="" element="" in="" last="" position
="" numofinvestors++;="" increment="" numofinvestors
="" delete="" []="" investorslist;="" old="" list
="" for(="" i="0;" i<="" numofinvestors;="" i++)
="" {
="" investorslist[i]="temp[i];" 
="" insertionsort(investorslist,="" numofinvestors);
="" investorslist[numofinvestors];="" numofinvestors++;
}="" <\pre="">

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