Re: Class/struct declarations and bit patterns [modified] - C / C++ / MFC Discussion Boards

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Re: Runtime error - incompatible iterator - why???

Philstix20-Dec-07 15:34

Philstix

20-Dec-07 15:34

Ok, the code that fails in Visual C++ 2005 Express is (if this formats ok):

vector < vector < string > > ::iterator vvsi_b = (a.Block()).begin();
vector < vector < string > > ::iterator vvsi_e = (a.Block()).end();
for (; vvsi_b != vvsi_e; ++vvsi_b)
{
// can be anything or nothing in the for loop - same result
}

Any idea why this causes the runtime error "Debug Assertion Failed! ... Expression: vector iterators incompatible" ?

Phil

Re: Runtime error - incompatible iterator - why???

Stephen Hewitt20-Dec-07 15:36

Stephen Hewitt

20-Dec-07 15:36

Where is the assertion happening? What line in your code?

Steve

Re: Runtime error - incompatible iterator - why???

Philstix20-Dec-07 17:28

Philstix

20-Dec-07 17:28

Thanks for replying.

The assertion isn't in my code as such it's in line 238 of the vector header file:

#if _HAS_ITERATOR_DEBUGGING
	void _Compat(const _Myt& _Right) const
		{	// test for compatible iterator pair
		if (this->_Mycont == 0 || this->_Mycont != _Right._Mycont)
			{
			_DEBUG_ERROR("vector iterators incompatible"); // line 238
			_SCL_SECURE_INVALID_ARGUMENT;
			}
		}
 #endif /* _HAS_ITERATOR_DEBUGGING */

I assume I could somehow disable iterator debugging to get around this error, but I would like to know why I'm getting the error in the first place. Am I doing something wrong? The iterators both come from the same vector object, so how could they be incompatible?

Phil

Class/struct declarations and bit patterns

Anthony Appleyard20-Dec-07 10:43

Anthony Appleyard

20-Dec-07 10:43

In a class or struct declaration in Visual C++ 2008, for example

class BMPheader{public: char BM[2]; long size; short u,v; long imagestart;};

or

struct BMPheader{char BM[2]; long size; short u,v; long imagestart;};

can I trust on that being an accurate description of the resulting byte pattern inside the computer, to match the format of a binary file that is read in? My experience here is:

Gnu C++ for DOS: no, because after each element was inserted 0 or 1 or 2 or 3 unused bytes, to get each byte to start at an address which was a multiple of 4, unless I inserted a special keyword to tell the compiler to pack the elements close.

Borland C++ 4.5 for Windows: yes.

Re: Class/struct declarations and bit patterns

CPallini20-Dec-07 11:19

CPallini

20-Dec-07 11:19

You have not to worry about alignment, as far you are consistent on writing to and reading from file, for instance (error handling left to the reader)

struct BMPHeader bmphout;
// assign struct members
...
FILE * fpout = fopen("foo.bin", "wb");
fwrite( &bmphout, sizeof(bmphout),1, fpout);
fclose(fpout);

and then

struct BMPHeader bmphin;
FILE * fpin = fopen("foo.bin", "rb");
fread( &bmphin, sizeof(bmphin),1, fpin);
// Now bmphin contains exactly the same data of original bmphout
fclose(fpin);

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.

[my articles]

Re: Class/struct declarations and bit patterns

Anthony Appleyard20-Dec-07 11:56

Anthony Appleyard

20-Dec-07 11:56

But here I am reading from a file format which someone else (probably at Microsoft many years ago) invented. So I need to know how to make Visual C++ 2008 compile a struct or class with the elements in the same order as declared with no extra bytes inserted between.

Good Luck!

CPallini20-Dec-07 12:45

CPallini

20-Dec-07 12:45

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.

[my articles]

Re: Class/struct declarations and bit patterns [modified]

Mark Salsbery20-Dec-07 13:22

Mark Salsbery

20-Dec-07 13:22

Anthony Appleyard wrote:
But here I am reading from a file format which someone else (probably at Microsoft many years ago) invented.

Why are you not using the Microsoft structure definitions
that have been around just as long?

BITMAPFILEHEADER is packed with 2-byte alignment
BITMAPINFO and BITMAPINFOHEADER are packed with 1-byte alignment.

To see how that affects struct padding and alignment, see

align (C++)[^]
/Zp (Struct Member Alignment)[^]
etc...

If you're going to redefine these structs and expect them to match
everyone else, then you'll probably want to set your structure packing
the same as Microsoft's (see #pragma pack).

*edit*  Also, using platform-specific types like "long" and "short" is a bad<br />
idea if you expect to match the Microsoft definitions.

Mark

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

modified on Thursday, December 20, 2007 7:40:28 PM

After a picture is tranformed by GDI+, mouse cursor point problem

followait20-Dec-07 5:57

followait

20-Dec-07 5:57

Like DPtoLP, how to do it with GDI+,
use TransformPoints?

Re: After a picture is tranformed by GDI+, mouse cursor point problem

CPallini20-Dec-07 10:16

CPallini

20-Dec-07 10:16

Yes, it looks promising.
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.

[my articles]

plzz hlep

coderwizard20-Dec-07 3:45

coderwizard

20-Dec-07 3:45

i has need code for windoz service when starting os.plz send politly.

Re: plzz hlep

George L. Jackson20-Dec-07 4:54

George L. Jackson

20-Dec-07 4:54

I think you should search the web before asking here. Your search keys are "c++ windows service"!

http://weblogs.asp.net/kennykerr/archive/2004/05/18/134342.aspx[^]

"We make a living by what we get, we make a life by what we give." --Winston Churchill

Re: plzz hlep

coderwizard20-Dec-07 5:19

coderwizard

20-Dec-07 5:19

Thank you for link sir. I search web also.

Re: plzz hlep

fearless20-Dec-07 5:05

fearless

20-Dec-07 5:05

0x2A3F

Re: plzz hlep

C^hris L^osinger20-Dec-07 5:10

C^hris L^osinger

20-Dec-07 5:10

oh hai!
would you like cheezeburger insted?

image processing toolkits | batch image processing

Re: plzz hlep

leckey20-Dec-07 5:15

leckey

20-Dec-07 5:15

Iz can have cheeseburger?

Current Rant: "Oh crap! I forgot Iowa!"
http://craptasticnation.blogspot.com/[^]

Re: plzz hlep

David Crow20-Dec-07 5:25

David Crow

20-Dec-07 5:25

No, Iz (mini Izzy?) cannot have a cheeseburger. This is not the food forum.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: plzz hlep

leckey20-Dec-07 6:38

leckey

20-Dec-07 6:38

I thought the original was "Iz" but I was wrong.
http://lolcats.com/view/56/[^]

Current Rant: "Oh crap! I forgot Iowa!"
http://craptasticnation.blogspot.com/[^]

Re: plzz hlep

CPallini20-Dec-07 5:21

CPallini

20-Dec-07 5:21

plzz chzzzburger!!!!
Big Grin | :-D

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.

[my articles]

Re: plzz hlep

Hamid_RT20-Dec-07 5:27

Hamid_RT

20-Dec-07 5:27

Is this good for windows service?

Re: plzz hlep

CPallini20-Dec-07 5:59

CPallini

20-Dec-07 5:59

Is good service anyway, with or without nearby windows
Big Grin | :-D

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.

[my articles]

Re: plzz hlep

Hamid_RT20-Dec-07 6:45

Hamid_RT

20-Dec-07 6:45

Yeah

Re: plzz hlep

Mark Salsbery20-Dec-07 5:15

Mark Salsbery

20-Dec-07 5:15

Doesn't windoz have an 'e' at the end?

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

Re: plzz hlep