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It would help if I knew what you're trying to achieve but yes, generally you'd call BindToObject. In other scenarios you'd call BindToStorage.
Steve
modified on Thursday, December 20, 2007 9:33:44 PM
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Hi,
I'm getting some terrible performance when calling ifstream close. It takes about the same amount of time to close() as it takes to read my 64 Mb of data! I've been playing around with it and found it only happens if I have been writing to a file recently. Here's my test code:
void readTest(const std::string & path)
{
ifstream in;
in.open(path.c_str(), ios_base::in | ios_base::binary);
char * buffer = new char[67108864];
in.read(buffer, 67108864);
SW_ELAPSED_MSG()
in.close();
SW_ELAPSED_MSG()
delete [] buffer;
}
void writeTest(const std::string & path)
{
ofstream out;
out.open(path.c_str(), ios_base::out | ios_base::binary);
char * buffer = new char[67108864];
out.write(buffer, 67108864);
out.close();
delete [] buffer;
}
int _tmain(int argc, _TCHAR* argv[])
{
writeTest("testfile");
SW_START();
readTest("testfile");
SW_ELAPSED_MSG()
return 0;
}
Note my macros do the timing and display it on screen. I don't believe there's any problem with that code.
So anyone know why? I'm closing the streams. Why is the read stream affected at all by the write stream? Also as you can see I have a flush() statement in there. It doesn't help, commented or not.
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Hi,
I'm stumped.
Why does this code compile without problems but cause a runtime error? ("Debug Assertion Failed! ... Expression: vector iterators incompatible")
<br />
vector< vector<string> >::iterator vvsi_b = (a.Block()).begin();<br />
vector< vector<string> >::iterator vvsi_e = (a.Block()).end();<br />
<br />
for (; vvsi_b != vvsi_e; ++vvsi_b)<br />
{<br />
}<br />
</string></string>
a.Block() returns a const reference to a vector< vector< string > > object
I'm using Visual C++ 2005 Express.
Any help (and consequent hair retention) greatly appreciated.
Phil
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Correction:
The quoted code should be:
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)
{
// etc.
}
Phil
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The codeproject message parser keeps removing part of the code I'm posting.
The code should refer to a vector of vector of string, but the string part keeps being removed from the post. How do I post so the code stays the way I want?
Phil
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Member 73301 wrote: The code should refer to a vector of vector of string, but the string part keeps being removed from the post. How do I post so the code stays the way I want?
post code snippets between <pre> TAGS, i.e.
<pre>
...code here..
...code here...
</pre>
also when showing templates use the escape sequence for < (<).
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]
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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)
{
}
Any idea why this causes the runtime error "Debug Assertion Failed! ... Expression: vector iterators incompatible" ?
Phil
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Where is the assertion happening? What line in your code?
Steve
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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
{
if (this->_Mycont == 0 || this->_Mycont != _Right._Mycont)
{
_DEBUG_ERROR("vector iterators incompatible");
_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
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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.
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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;
...
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);
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]
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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.
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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]
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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]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif)
modified on Thursday, December 20, 2007 7:40:28 PM
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Like DPtoLP, how to do it with GDI+,
use TransformPoints?
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Yes, it looks promising.
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]
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i has need code for windoz service when starting os.plz send politly.
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Thank you for link sir. I search web also.
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oh hai!
would you like cheezeburger insted?
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Iz can have cheeseburger?
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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
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plzz chzzzburger!!!!
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]
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