ATL / WTL / STL

7-Dec-06 16:29

I not created any object in my program, but I found memory leak. Why?
I wonder whether the stl in VC6.0 can be available.

The source code is as follow. If you run it in VC6.0, you may find the memory leak prompt in output box. Why?
// TestMemLeak.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

#include <stdio.h>
#include <vector>
#include "srmcritsec.h"

#define _CRTDBG_MAP_ALLOC
#include<stdlib.h>
#include<crtdbg.h>

typedef struct ipqam
{
char szName[50];
char szIpAddr[50];
char szDistrictName[50];
char szNote[255];
}IPQAM;

typedef struct freqpoint
{
char szName[50];

// added by yangyi,2006-8-23
int32 Modulate;

int32 Freq;
int32 Symbolrate;
char szNote[255];

}FREQPOINT;

/*
****************************************************************
struct : interfreqpoint
****************************************************************
*/
typedef struct interfreqpoint
{
FREQPOINT freqpoint;
// CSrmCritSec sec;

interfreqpoint();
interfreqpoint(const interfreqpoint & obj);

~interfreqpoint();

interfreqpoint & operator=(const interfreqpoint & obj);
}INTERFREQPOINT;

interfreqpoint::~interfreqpoint()
{

}

/*
function : constructor
*/
interfreqpoint::interfreqpoint(const interfreqpoint & obj)
{
*this = obj;
}

/*
function : constructor
*/
interfreqpoint::interfreqpoint()
{
this->freqpoint.Freq = 0;
this->freqpoint.Modulate = 0;
this->freqpoint.Symbolrate = 0;
this->freqpoint.szName[0] = 0;
this->freqpoint.szNote[0] = 0;
}

/*
function : overload =
*/
interfreqpoint & interfreqpoint::operator=(const interfreqpoint & obj)
{
strcpy(freqpoint.szName,obj.freqpoint.szName);
strcpy(freqpoint.szNote,obj.freqpoint.szNote);
freqpoint.Freq = obj.freqpoint.Freq;
freqpoint.Modulate = obj.freqpoint.Modulate;
freqpoint.Symbolrate = obj.freqpoint.Symbolrate;
return * this;
}

/*
****************************************************************
struct : interipqam
****************************************************************
*/
typedef struct interipqam
{
IPQAM qam;
std::vector<interfreqpoint> freqpointarray;
// CSrmCritSec sec;

interipqam(const interipqam & obj);

interipqam();

~interipqam();

interipqam & operator=(const interipqam & obj);

}INTERIPQAM;

interipqam::interipqam(const interipqam & obj)
{
*this = obj;
}

interipqam::~interipqam()
{
freqpointarray.clear();
}

interipqam::interipqam()
{
qam.szDistrictName[0] = 0;
qam.szIpAddr[0] = 0;
qam.szName[0] = 0;
qam.szNote[0] = 0;
}

interipqam & interipqam::operator=(const interipqam & obj)
{

INTERFREQPOINT objFp;
int32 nCnt = obj.freqpointarray.size(),nLoop = 0;

strcpy(qam.szDistrictName,obj.qam.szDistrictName);
strcpy(qam.szIpAddr,obj.qam.szIpAddr);
strcpy(qam.szNote,obj.qam.szNote);
strcpy(qam.szName,obj.qam.szName);

freqpointarray.clear();

for(nLoop = 0;nLoop < nCnt; nLoop++)
{
objFp = obj.freqpointarray.at(nLoop);
freqpointarray.push_back(objFp);
}

return *this;
}

int main(int argc, char* argv[])
{
_CrtDumpMemoryLeaks();

printf("Hello World!\n");
return 0;
}

yangyi

YangHenry7-Dec-06 16:33

7-Dec-06 16:33

The source code is as follows.

#include "stdafx.h"
#include <stdio.h>
#include <vector>

#define _CRTDBG_MAP_ALLOC
#include<stdlib.h>
#include<crtdbg.h>

typedef struct ipqam
{
char szName[50];
char szIpAddr[50];
char szDistrictName[50];
char szNote[255];
}IPQAM;

typedef struct freqpoint
{
char szName[50];

// added by yangyi,2006-8-23
int Modulate;

int Freq;
int Symbolrate;
char szNote[255];

}FREQPOINT;

/*
****************************************************************
struct : interfreqpoint
****************************************************************
*/
typedef struct interfreqpoint
{
FREQPOINT freqpoint;
// CSrmCritSec sec;

interfreqpoint();
interfreqpoint(const interfreqpoint & obj);

~interfreqpoint();

interfreqpoint & operator=(const interfreqpoint & obj);
}INTERFREQPOINT;

interfreqpoint::~interfreqpoint()
{

}

/*
function : constructor
*/
interfreqpoint::interfreqpoint(const interfreqpoint & obj)
{
*this = obj;
}

/*
function : constructor
*/
interfreqpoint::interfreqpoint()
{
this->freqpoint.Freq = 0;
this->freqpoint.Modulate = 0;
this->freqpoint.Symbolrate = 0;
this->freqpoint.szName[0] = 0;
this->freqpoint.szNote[0] = 0;
}

/*
function : overload =
*/
interfreqpoint & interfreqpoint::operator=(const interfreqpoint & obj)
{
strcpy(freqpoint.szName,obj.freqpoint.szName);
strcpy(freqpoint.szNote,obj.freqpoint.szNote);
freqpoint.Freq = obj.freqpoint.Freq;
freqpoint.Modulate = obj.freqpoint.Modulate;
freqpoint.Symbolrate = obj.freqpoint.Symbolrate;
return * this;
}

/*
****************************************************************
struct : interipqam
****************************************************************
*/
typedef struct interipqam
{
IPQAM qam;
std::vector<interfreqpoint> freqpointarray;
// CSrmCritSec sec;

interipqam(const interipqam & obj);

interipqam();

~interipqam();

interipqam & operator=(const interipqam & obj);

}INTERIPQAM;

interipqam::interipqam(const interipqam & obj)
{
*this = obj;
}

interipqam::~interipqam()
{
freqpointarray.clear();
}

interipqam::interipqam()
{
qam.szDistrictName[0] = 0;
qam.szIpAddr[0] = 0;
qam.szName[0] = 0;
qam.szNote[0] = 0;
}

interipqam & interipqam::operator=(const interipqam & obj)
{

INTERFREQPOINT objFp;
int nCnt = obj.freqpointarray.size(),nLoop = 0;

strcpy(qam.szDistrictName,obj.qam.szDistrictName);
strcpy(qam.szIpAddr,obj.qam.szIpAddr);
strcpy(qam.szNote,obj.qam.szNote);
strcpy(qam.szName,obj.qam.szName);

freqpointarray.clear();

for(nLoop = 0;nLoop < nCnt; nLoop++)
{
objFp = obj.freqpointarray.at(nLoop);
freqpointarray.push_back(objFp);
}

return *this;
}

int main(int argc, char* argv[])
{
_CrtDumpMemoryLeaks();

printf("Hello World!\n");
return 0;
}

yangyi

YangHenry7-Dec-06 16:36

7-Dec-06 16:36

If you hide the for loop in InterIpqam::opertator=(),and then you rebuild and debug it, you maynot find the memory leak prompt in output box. Why?
I am very puzzled.

yangyi

Stuart Dootson7-Dec-06 21:11

7-Dec-06 21:11

When you post code, can you (please) use a setting where your #include angle brackets don't get converted to tags - the "Ignore HTML tags in this message (good for code snippets)" checkbox should be checked
There will be no memory leaks in the code you've posted - it doesn't actually use any of your structs
I added some code to instantiate some interipqam items and assign them - there were no memory leaks that I could see.

I think you can be reasonably confident that std::vector works as advertised, at least as far as allocating memory goes.

YangHenry7-Dec-06 22:15

7-Dec-06 22:15

Firstly, thanks for your answer.
Secondly, let me go on with my question.
Of course, I know it not creat any objects, so it doesn't have any memory leak.
But in vc's output when you debug it, you may find memory leak prompt info.
I copy the prompt info here.

Detected memory leaks!
Dumping objects ->
{42} normal block at 0x00441F70, 33 bytes long.
Data: < C > 00 43 00 CD CD CD CD CD CD CD CD CD CD CD CD CD
{41} normal block at 0x00441FC0, 40 bytes long.
Data: < |L > 14 7C 4C 10 16 00 00 00 00 00 00 00 00 00 00 00
Object dump complete.

So I wonder why?Can u tell me the cause? Thanks

yangyi

Stuart Dootson8-Dec-06 0:37

help me! I don't obtain the point of IHTMLElement through IHTMLDOMNode! why? [modified]

8-Dec-06 0:37

I didn't have any memory leak information when I ran your code. However, to find the source of those leaks, you could try using _CrtSetBreakAlloc to get the runtime to break when the relevant memory allocation is performed. Looking at your text, you need to look for allocations 41 and 42 (the numbers inside the curly brackets).

However, I think you'll find those allocations are made by the C runtime library *before* your code is ever called (I compiled a console application with the line int* a = new int; and that was allocation number 88), so they aren't allocations you need to worry about, because the runtime library clears them *after* your code exits.

guti_milan7-Dec-06 16:06

guti_milan

7-Dec-06 16:06

my code:

<code>CComQIPtr<IHTMLDOMNode>pRootNode(lpParentDisp);

CComPtr<IDispatch> spChildren;
if(FAILED(pRootNode->get_childNodes(&spChildren)))return;
CComQIPtr<IHTMLDOMChildrenCollection> pChildColl(spChildren);

long lCount = 0;
pChildColl->get_length(&lCount);
for (long l = 0;l<lCount;l++)
{
CComPtr<IDispatch> spChild;
pChildColl->item(l,&spChild);
CComQIPtr<IHTMLDOMNode> pChild(spChild);
CComQIPtr<IHTMLElement> pElement(pChild); // I don't obtain the point

}</code>
please somebody help me ! thanks........

-- modified at 22:14 Thursday 7th December, 2006

I'm a good man!

-- modified at 22:15 Thursday 7th December, 2006

Web deployment

Polity4h6-Dec-06 10:53

Polity4h

6-Dec-06 10:53

Hi,

I've created a com object in ATL ( still learning ). However, somethimes you get to see such nice online installers.
Someone goes to a specific page, gets the error that he needs some files installed on his computer. then in iexplore, a nice goldbar kicks in wich automaticly sends you the nessesary files on accept. even better, they totally install and register themselfs. So how can i create this? i'm using apache 2.* on a debian linux server ( sorry, trying to jump to winserv 2003 any time now )

Re: Web deployment

hanmengguo7-Dec-06 15:12

hanmengguo

7-Dec-06 15:12

1 .write a inf file like this sample:
; Sample INF file for AVJumbee.dll
[version]
; version signature (same for both NT and Win95) do not remove
signature="$Chicago$"
AdvancedINF=2.0

[Add.Code]
AsiaViewFTPCtrl.dll=AsiaViewFTPCtrl.dll /// com dll

; needed DLL
[AsiaViewFTPCtrl.dll]
file-win32-x86=thiscab
clsid={42FD5C77-532D-4BB0-A284-F0D8FB124049} // com guid
FileVersion=1,00,0,3
RegisterServer=yes

; end of INF file

2 download CabArc.Exe file
3 run cmd:CABARC -s 6144 n AsiaViewFTPCtrl.CAB AsiaViewFTPCtrl.dll AsiaViewFTPCtrl.INF //make a .CAB file
4 codesign2005 tools
5 put the sign cab file to web

hi

Re: Web deployment

Polity4h8-Dec-06 3:26

Polity4h

8-Dec-06 3:26

thanks, gonna test it asap

Help, How to make a Window to behave like a dialog without using dialog resource?

Skywalker20084-Dec-06 3:43

Skywalker2008

4-Dec-06 3:43

I used CWindow::Create() to build a new POPUP window in VC++6.0/WTL. I wanted to
make the window behave like a dialog without using a dialog resource template. By behave like a dialog, I mean the running process suspends until the dialog window returns/closed.

Can you please help me with that? Thanks.

Re: Help, How to make a Window to behave like a dialog without using dialog resource?

Alain Rist5-Dec-06 16:53

Alain Rist

5-Dec-06 16:53

Hi,
In http://tech.groups.yahoo.com/group/wtl/files/EmptyDlg.h[^] you will find a minimal CEmptyDialogImpl class which you may derive from:
class CMyEmptyDialog : public CEmptyDialogImpl<CMyEmptyDialog, uMyIDD>
cheers,
AR

STL list and sort

neilsolent1-Dec-06 8:18

neilsolent

1-Dec-06 8:18

Gurus,

If I have an STL list (doesn't matter what of) and I sort it, how can I add one element to the list, whilst maintaining the sort order?

All I can think of to achieve this is to either: (1) add the new element to one end, and run sort() again, or (2) iterate through the entire list, checking the sort predicate against each element. Neither of these seem particulalrly appealing.

Does anyone know the most processor efficient way of doing this please ?

thanks,

Neil.

cheers,
Neil

led mike1-Dec-06 8:36

led mike

1-Dec-06 8:36

They hide that information in the documentation[^]

Lower_bound is a version of binary search: it attempts to find the element value in an ordered range [first, last) [1]. Specifically, it returns the first position where value could be inserted without violating the ordering.

However that might not be the "most efficient" for your application. There are several things to consider. If you use STL much you should have Scott Meyers book as it discusses efficiency issues.

led mike

neilsolent1-Dec-06 9:57

neilsolent

1-Dec-06 9:57

Thanks for that answer,

Neil

cheers,
Neil

Stuart Dootson2-Dec-06 14:10

2-Dec-06 14:10

led mike wrote:
However that might not be the "most efficient" for your application.

It probably won't be - I don't think the structure of std::list iterators is terribly conducive to binary searches - could be wrong, mind.

Zac Howland5-Dec-06 9:36

Zac Howland

5-Dec-06 9:36

Stuart Dootson wrote:
It probably won't be - I don't think the structure of std::list iterators is terribly conducive to binary searches - could be wrong, mind.

std::deque would probably be a better choice in most cases.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Sceptic Mole1-Dec-06 8:42

Sceptic Mole

1-Dec-06 8:42

neilsolent wrote:
f I have an STL list (doesn't matter what of) and I sort it, how can I add one element to the list, whilst maintaining the sort order?
All I can think of to achieve this is to either: (1) add the new element to one end, and run sort() again, or (2) iterate through the entire list, checking the sort predicate against each element. Neither of these seem particulalrly appealing.
Does anyone know the most processor efficient way of doing this please ?

If you insert only one element (2) is probably faster. You can make it even faster if you know from which end to start.

neilsolent1-Dec-06 9:58

neilsolent

1-Dec-06 9:58

Thanks for that answer.

Unfortunately there will be no way of knowing which end to start from.

Neil

cheers,
Neil

Stuart Dootson2-Dec-06 14:08

2-Dec-06 14:08

Best bet is to guess by seeing if it's closer in value to front() or back(). That way, the average search distance for random data will be N/2 where N is the list length.