Re: Stack overflows - C / C++ / MFC Discussion Boards

Re: Stack overflows

David Crow3-Mar-06 4:33

David Crow

3-Mar-06 4:33

At the point the program crashes, look at the call stack (within the IDE) to get a better idea of where the problem is.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: Stack overflows

Waldermort3-Mar-06 4:57

Waldermort

3-Mar-06 4:57

I know this probably means nothing, but this is the top end of the call stack

USER32! 77d61ee3()
USER32! 77d43a68()
USER32! 77d43b37()
USER32! 77d4546b()
USER32! 77d5a3aa()
USER32! 77d5a4f0()
USER32! 77d43a68()
USER32! 77d43b37()
USER32! 77d4546b()
USER32! 77d45f69()
cDisplay::get_student_id(std::vector<_RECORD,std::allocator<_RECORD> > & {...}) line 510 + 24 bytes
cParse::display_student_record() line 633 + 18 bytes
DlgProc(HWND__ * 0x001c0698, unsigned int 78, unsigned int 1000, long 210508) line 103

which suggets to me that the problem is within USER32. But then again I may be wrong. Any ideas?

Re: Stack overflows

David Crow3-Mar-06 5:56

David Crow

3-Mar-06 5:56

This does not even show that add_list_item() is being called at the time of the stack overflow. It's almost like the code is having trouble accessing one of the vector items. What if you print out the contents of the vector like:

for (long i = 0; i < rec.size(); i++)
{    
    OutputDebugString(rec[i].text);    
    OutputDebugString("\r\n");
}

The second thing to try is adding the items outside of the for loop like:

add_list_item(0, 0,0,rec[0].text);
add_list_item(1, 0,0,rec[1].text);
...
add_list_item(33, 0,0,rec[33].text);

Try also removing the calls to ListView_SetColumnWidth() and InvalidateRect(). What happens if you did something like:

for (long i = 32; i < rec.size(); i++)
    add_list_item(i - 32, 0, 0, rec[i].text);

which starts with the 33rd item in the vector.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: Stack overflows

Waldermort3-Mar-06 6:18

Waldermort

3-Mar-06 6:18

When taking everything out of the loop the 32nd call to add_list_item causes a stack overflow. All of the items in the vector are present and correct, and changing the value of i makes no difference.

When stepping through the code it enters the add_list_item function, all the variables and memory are exactly the same as the previous calls, nothing changes, but as soon as it sends the LVM_INSERTITEM message, it causes a stack overflow.

Re: Stack overflows

David Crow3-Mar-06 6:35

David Crow

3-Mar-06 6:35

waldermort wrote:
When taking everything out of the loop the 32nd call to add_list_item causes a stack overflow.

So, is it because the list view already has 31 other items in it, or is there something special about the 32nd item. Can you isolate these two?

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: Stack overflows

Waldermort3-Mar-06 15:59

Waldermort

3-Mar-06 15:59

Sorry maybe I phrased that a little wrong, I should have said that everything up to the 32nd item is displayed, theron after I start getting the "stack overflow" errors. I have tried breaking out of the loop if i is 32, starting the loop from the 32nd item. Nn matter what I do, only on the 32nd call to add_list_item the program crashes.

Re: Stack overflows

Waldermort3-Mar-06 5:53

Waldermort

3-Mar-06 5:53

Just an update. I have changed my code slightly so that now the loop is reversed and all the inserting to the listbox is added at position 0. This draws the list exactly as it should, but when scrolling through the list (using the direction keys), the program crashes again "stack overflow". At this point I am pretty sure that the problem lies within user32.dll and not my code.

Is it possible to update this dll without having to update the whole system or go through the whole windows update pollava? Mine is version 5.1.2600.1106, I am curious to know if the problem exists in later versions. If this is the case I would probably have to change my code to check for the verion and update it, how would one do this?

Re: Stack overflows

David Crow3-Mar-06 5:59

David Crow

3-Mar-06 5:59

Ok, what happens to rec after the list view has been populated? Is it a global variable that hangs around, or is it local to some function that gets destroyed after it's been used?

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Re: Stack overflows

Waldermort3-Mar-06 6:28

Waldermort

3-Mar-06 6:28

rec is a vector of some 150 structs each of which contain approx members of type char pointers. Before this function is called the vector is populated within another class and is never destroyed nor are the contents changed in any way.

Infact the add_list_item function is the only function in the program which has access to this vector.

std c++ structures

Peter Charlesworth3-Mar-06 3:29

Peter Charlesworth

3-Mar-06 3:29

Hi!

I am new to structures and I get how they work, sort of. And I have a question.
Let's say I've got this structure:

<br />
struct person<br />
  { string name;<br />
    int eye_colour;<br />
    float height;<br />
  };<br />
<br />
person friend,mother;<br />
person spouse;<br />

Note that eye color is defined by a number. 1 is brown, 2 is blue, 3 is green and a NULL value is
an unknown eye color, or whatever you like.

So how can I make my program create a new person, which is user-inputted?
Something like this: ?

<br />
cin.get(newpersonname, 15)<br />
cin.ignore(16,'\n')<br />
create.person (newpersonname)<br />

And how would that work for structures within structures?

I'm kinda confused on this Confused | :confused:

thanks!

Peter

Re: std c++ structures

Cedric Moonen3-Mar-06 3:38

Cedric Moonen

3-Mar-06 3:38

You cannot do that. What you have to do is read to several different members of your struct and supply them to your structure.
You can eventually go for operator overloading but I don't think in this case it is really appropriate.

Re: std c++ structures

Peter Charlesworth3-Mar-06 12:02

Peter Charlesworth

3-Mar-06 12:02

Thank for the responses, guys, but everyone seems
to be worried about the eye color, which was
merely an example.
But if it's truly impossible to create "fields" or
"members" or whatever you call the things
like friend and mother and spouse in my
example, then my program is going to end
in tears, I'm afraid...

Well, thank, anyways!

Re: std c++ structures

Maximilien3-Mar-06 3:39

Maximilien

3-Mar-06 3:39

Peter Charlesworth wrote:
and a NULL value is
an unknown eye color, or whatever you like.

I would recommend using -1 instead of a NULL because NULL makes no sense with int; or better, use an enum.

to answer your question try something like :

person mother;
mother.name = "Mom";
mother.eye_colour = 1;
mother.height = 1.34;

Maximilien Lincourt
Your Head A Splode - Strong Bad

Re: std c++ structures

Peter Charlesworth3-Mar-06 12:06

Peter Charlesworth

3-Mar-06 12:06

Thank for your answer but I was asking if it were possible
to create a new person whilst the program is running.
For instance, the user wishes to create a new person,
co-worker for instance, which uses the person structure.
Is it possible to create a new one without defining
it in the source code?

Thanks anyways!

Re: std c++ structures

toxcct3-Mar-06 3:49

toxcct

3-Mar-06 3:49

struct person {
    string name;
    typedef enum {
        BROWN = 1,
        BLUE  = 2,
        GREEN = 3
    } eyeColors_t;
    eyeColors_t eye_colour;
    float height;
 
    friend istream& operator >> (const istream&, const person&);
};
 
istream& operator >> (istream& is, const person& p) {
    is >> name >> eye_colour >> height;
    return is;
}

Re: std c++ structures

Peter Charlesworth3-Mar-06 12:04

Peter Charlesworth

3-Mar-06 12:04

Hmmm... that piece of code has given me an idea...
Thanks, V2.0 !

Re: std c++ structures

markkuk3-Mar-06 12:18

markkuk

3-Mar-06 12:18

Define a constructor for your struct that takes name, eye_color and height as parameters (and has default values for all of them).

struct person
{
    string name;
    int eye_colour;
    float height;
    person(const string& n = "" , int e = -1 , float h = 0.0F);
};
person::person(const string& n, int e, float h)
: name(n), eye_color(e), height(h)
{}

Now you can create new instances of person easily:

person* spouse;
string newpersonname;
cin.get(newpersonname, 15);
cin.ignore(16,'\n');
spouse = new person(newpersonname);

Re: std c++ structures

Peter Charlesworth3-Mar-06 12:29

Peter Charlesworth

3-Mar-06 12:29

Hmmm...
Does the second bit of code take 'spouse' as an example to make
'newpersonname' or does it erase 'spouse' in order to replace it
with 'newprersonname'?

Thanks anyways!

Does kernel driver can invoke GetLogicalDriveStrings()?

momer3-Mar-06 3:20

momer

3-Mar-06 3:20

GetLogicalDriveStrings() can be used to get system driver stirngs in user mode app,if it can be used in driver program to do the same thing?
Thanks!

changing brush attributes at runtime

pc_dev3-Mar-06 2:09

pc_dev

3-Mar-06 2:09

In my application i need to change brush attributes e.g color etc at run time,

consider following

CBrush b1;
b1.createSolidBrush(RGB(255,0,0));

now how can i change the color of same brushto green color?

An alternate option is to create new brush when it is needed and then destroy when its not, but this creation/destruction will slow down the prog, thats why i want to use only one brush and change its attributes as needed at run time

Thanks in advance Rose | [Rose]

Re: changing brush attributes at runtime

C^hris L^osinger3-Mar-06 2:15

C^hris L^osinger

3-Mar-06 2:15

pc_dev wrote:
An alternate option is to create new brush when it is needed

or create them both at the start of your app, and destroy them both at the end

Cleek | Image Toolkits | Thumbnail maker

[OT]

toxcct3-Mar-06 2:35

toxcct

3-Mar-06 2:35

hi Chris,

this has nothing to deal with the question you answered, but i wanted to know if you had received my mail, and if you have any particulier thoughts about it...

thanks,

v2.0

Re: [OT]

C^hris L^osinger3-Mar-06 3:03

C^hris L^osinger

3-Mar-06 3:03

hmmm... i don't think i did. i will check my Junk folders (my spam filter is a bit too aggressive sometimes)

Cleek | Image Toolkits | Thumbnail maker

Re: changing brush attributes at runtime

pc_dev3-Mar-06 3:26

pc_dev

3-Mar-06 3:26

Thanks for reply.

Chris Losinger wrote:
create them both at the start of your app, and destroy them both at the end

If there were only two brushes needed then I would do the same but in my case i can't tell how much brushes will be needed, eg 1000.

in above case the best option is to create on eand change its attributes at run time.

Re: changing brush attributes at runtime

C^hris L^osinger3-Mar-06 3:53

C^hris L^osinger

3-Mar-06 3:53

pc_dev wrote:
in above case the best option is to create on eand change its attributes at run tim

except that it's probably not possible to do that.

Cleek | Image Toolkits | Thumbnail maker

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