C / C++ / MFC

Help with setting values to char arrays (strings);

5-Feb-06 1:11

http://www.codeguru.com/Cpp/controls/[^]

Enjoy Rose | [Rose]

Anderson Sheen (exteide@gmail.com)
The Extension IDE: http://www.exteide.com

memory leak with dll

Rhiakath4-Feb-06 14:43

Rhiakath

4-Feb-06 14:43

Hi there. I have a question that has been unanswered for too long. Suppose I have an application that uses a DLL, and within that application, I need to pass a STL string to a class within the DLL. Have you tried that?? It blows up. Now, how can I get over this. This thing works until it leaves the function, making me believe that it is something to do with the release of the memory used by the string itself. Now, I know I could pass a pointer, or whatever, but this is just an example. Right now, I'm trying to get a class within the DLL ask the main app for a STL map, and the app fills up the map correctly, but just when the dll function exits, it blows up again. and again, error deallocating the memory. I've built two mini-projects with VS .NET 2003 for you to check it out. They're very simple and show this error. Can you give me a hint here? Thanks

the link to the projects is here

Re: memory leak with dll

Stephen Hewitt4-Feb-06 18:29

Stephen Hewitt

4-Feb-06 18:29

Almost certainly you are experiencing the classic mixed allocator problem. That's when you allocate memory on one heap and free it in another - This is bad - A crash is the best cash scenario as often it results in heap corruption and "blows up" some time later in some other part of the code leaving you scratching your head. The general way around this is to follow this rule:
- If you allocate memory in one module free it in the same module. You may have to export a free function from the module to achieve this.

Another approach is that used by COM - All the modules agree to use the same allocator (CoTaskMemAlloc and friends. You could implement this for STL strings by writting a custom allocator (the allocator can be passed as a template parameter).

Steve

Re: memory leak with dll

Rama Krishna Vavilala5-Feb-06 6:47

Rama Krishna Vavilala

5-Feb-06 6:47

Make sure that you link all modules with the dll version of C++ runtime library.

printer problem

includeh104-Feb-06 14:25

includeh10

4-Feb-06 14:25

I print 2 base lines:
1) from (0,0) to (300,0) - horz base line
2) from (0,0) to (0,300) - vert base line

but they are not at topmost and leftmost of printed page - there are margins at top and left.

do you know how to adjust the base lines from C++ or hardware (printer etc) settings to delete the margins to let the 2 base lines at topmost and leftmost of printed page?

---------------------------
followins are MFC code, please do a testing for me: if your printers have margins also?
---------------------------
CPrintDialog cp(0);
if(cp.DoModal()!=IDOK) return;

HDC hDC=0;

hDC=cp.CreatePrinterDC();
if(hDC==0) return;

CDC*pDC=CDC::FromHandle(hDC);
int iMapMode=pDC->SetMapMode(MM_LOENGLISH);

DOCINFO docInf;
memset(&docInf,0,sizeof(DOCINFO));
docInf.cbSize=sizeof(DOCINFO);

pDC->StartDoc(&docInf);
pDC->StartPage();

pDC->MoveTo(0,0);
pDC->LineTo(300,0);
pDC->MoveTo(0,0);
pDC->LineTo(0,-300);

pDC->EndPage();
pDC->EndDoc();

pDC->SetMapMode(iMapMode);
-------------------------
thx

A nice tool for optimizing your Microsoft html-help contents.

Includeh10

Re: printer problem

Gary R. Wheeler5-Feb-06 2:04

Gary R. Wheeler

5-Feb-06 2:04

Most printers can't print on the entire page. Lasers typically have a 'border' from 0.1 to 0.3 inches around the edge where they won't print. Ink jets are similar.

Software Zen: delete this;

Fold With Us![^]

Coolarj104-Feb-06 10:07

Coolarj10

4-Feb-06 10:07

I have a problem with this code, if anyone could please help me out, I would greatly appreciate it! I'm trying to make a program that has a certain number of 'char arrays.' When the program starts, it's supposed to randomly concatentate any of the two strings. My program has a problem in four lines of code, and I don't understand how to do it any different. Thank you for your time and help! (P.S., though this snippet of code only shows 4 different strings, my actual program will have at least 25);

//Test program. The object of this program is to
//have different strings randomly concatenate

#include <iostream>
#include <windows.h>
using namespace std; //or #include <stdio.h>, depending on the compiler
#include <string.h>

int main()
{
srand(GetTickCount());
char word[4][128]; //I want to store different strings into word[0], word[1], word[2], and word[3]

word[0][128] = "word1"; //This is set of four lines is where the problem is
word[1][128] = "word2";
word[2][128] = "word3";
word[3][128] = "word4"; //----end of the problem

int firstword;
int secondword;

firstword = rand() % 4;
secondword = rand() % 4;

strcat(word[firstword], word[secondword]);

cout << ""<< word[firstword] <<"";

cin.ignore();

return 0;
}

Re: Help with setting values to char arrays (strings);

Gary R. Wheeler4-Feb-06 10:54

Gary R. Wheeler

4-Feb-06 10:54

First problem: The line word[0][128] = "word1"; doesn't assign the string "word1" to word[0], which is what I assume you want to do. These four lines probably shouldn't even compile, since on the left side of the assignment you are referencing a single character (word[0][128]) and on the right side you have a string constant.

Second problem: You can't assign simple strings in the way you have. In C/C++, for simple strings, you use the strcpy() function.

Here's that part of the code, cleaned up:

strcpy(word[0],"word1");
strcpy(word[1],"word2");
strcpy(word[2],"word3");
strcpy(word[3],"word4");

Software Zen: delete this;

Fold With Us![^]

Re: Help with setting values to char arrays (strings);

meinhard_risch4-Feb-06 13:14

Re: Help with setting values to char arrays (strings);

4-Feb-06 13:14

or try this

for(i=0;i<4;i++)
sprintf(word[i],"word%d",i);

Rose | [Rose]

Meinhard

Coolarj104-Feb-06 14:37

Coolarj10

4-Feb-06 14:37

Thank you so much everybody for your help! My program finally works thanks to your help!

Re: Help with setting values to char arrays (strings);

Gary R. Wheeler5-Feb-06 2:27

Gary R. Wheeler

5-Feb-06 2:27

You're welcome Rose | [Rose]

Software Zen: delete this;

Fold With Us![^]

Re: Help with setting values to char arrays (strings);

meinhard_risch5-Feb-06 3:45

html-based modless Windeow

5-Feb-06 3:45

MFC

sidkraft4-Feb-06 6:39

sidkraft

4-Feb-06 6:39

I am "drawing" shapes in the user area of display and want to erase all that I drew to-date. I set the variable ShapeKind to the type of curve, i.e. bezel, points or, if points, I set them all to zero and then issue "Invalidate". This erases the screen of any lines that I have drawn to-date. However, I was told to set ShapeKind but do not know how it is used or called within the "Invalidate" statement, any comments to Sid Kraft at sid_kraft@msn.com. Thanks Laugh | :laugh:

Sid

meinhard_risch4-Feb-06 6:22

4-Feb-06 6:22

Hi to you,
sorry about me very bad english. I'm looking for a way to include a html-based resource in a project and diplay it as an modless Window.
Can somebody help?

Meinhard Confused | :confused:

EXTEIDE4-Feb-06 9:40

4-Feb-06 9:40

use below in your .rc file:

TESTID RCDATA "htmlfile.html"

and use it in your code. m_hInstance can be NULL.

HRSRC h = FindResource(m_hInstance, "TESTID", RT_RCDATA);

if (!h)
{
HGLOBAL f = LoadResource(m_hInstance, h);
void* mem = LockResource(f);
int size = SizeofResource(m_hInstance, h);
}

and cook it.

Enjoy Rose | [Rose]

Anderson Sheen (exteide@gmail.com)
The Extension IDE: http://www.exteide.com

meinhard_risch4-Feb-06 13:32

4-Feb-06 13:32

Thank you very much!!

I tried it and it works fine! But as a stupid I am, my question now is, how to put it on the sreen in a window?

Thank you for helping again.

Meinhard
Smile | :)

EXTEIDE4-Feb-06 14:30

4-Feb-06 14:30

You're welcome. It's my pleasure.

you can save the resource to temporary file, and load it by using the MFCIE.

Or access it directly in MFCIE if it would work.

see the below msdn reference. you can download the sample.

http://msdn2.microsoft.com/en-us/library/ms177540(en-US,VS.80).aspx[^]

Enjoy Rose | [Rose]

Anderson Sheen (exteide@gmail.com)
The Extension IDE: http://www.exteide.com

meinhard_risch5-Feb-06 3:40

5-Feb-06 3:40

Thank you for your answer. But the difficulties never ends. The linked sample is written for Vers 8.0. I'm unable to use, because I#m only owner of the 7.0 Version of VS.

Hope you would help me again.

All the best

Meinhard
Wink | ;)

EXTEIDE5-Feb-06 3:58