Re: Dangling pointers and incorrect data being written - C / C++ / MFC Discussion Boards

Re: Dangling pointers and incorrect data being written

Stuart Dootson17-Dec-08 2:34

17-Dec-08 2:34

Mmmm - I'm not seeing what you're seeing - m_CacheBlocks retains its value. However, I've found some more issues in your code:

getCacheBlocks returns the cache-block vector by value - try returning by const reference instead:
```
vector<CacheBlock> const & getCacheBlocks() const;
```
Some of your setter functions take a uint by non-const reference - they should probably be by value (that's fine with plain old data like integers) or const reference. VC++ complained about it, anyway.

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa17-Dec-08 4:47

Mustafa Ismail Mustafa

17-Dec-08 4:47

I have taken your advice and currently have given up developing on Linux, I can't make good use of my time using IDEs that I don't have much experience in and on top of that using a language that I obviously am completely out of practice with (MUCH more so than I thought Cry | :((

)

I've moved back to Windows (VS2008) at least the debugger is something of an old friend. I'll keep you posted mate.

Thanks a zillion.

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Stuart Dootson17-Dec-08 5:18

Stuart Dootson

17-Dec-08 5:18

Mustafa Ismail Mustafa wrote:
I've moved back to Windows (VS2008) at least the debugger is something of an old friend

Can't say I blame you - even using GDB through Xcode felt...strange, given how used to Visual Studio I am!

Re: Dangling pointers and incorrect data being written [modified]

Mustafa Ismail Mustafa17-Dec-08 5:52

Mustafa Ismail Mustafa

17-Dec-08 5:52

I've pinpointed the exact location where the error takes place.

Guess what? Its a const correctness issue.

Simulator::CreateCacheSets()
{
...
getCacheSets[setIx].getCacheBlocks().push_back(getCacheBlocks()[i]);
...
}

getCacheBlocks() returns a const object. I'm surprised a compile time error was not thrown. Do I overload the method?

[update]
I've fixed it, but its the ugliest hack I've ever done.

<br />
//v[setIx].getCacheBlocks().push_back(getCacheBlocks()[i]);<br />
/*<br />
Can't do it this way, the getCacheBlocksMethod is const, so, we're doing it the crappy way<br />
which is making equivalent objects and setting them<br />
*/<br />
    vector<cacheblock> cbs;<br />
    for(uint i = 0; i < numBlocks; i++)<br />
    {<br />
        ba = getCacheBlocks()[i].getBlockAddress();<br />
        setIx = ba % numSets;<br />
        cbs = v[setIx].getCacheBlocks();<br />
	cbs.push_back(this->getCacheBlocks()[i]);<br />
	v[setIx].setCacheBlocks(cbs);<br />
    }<br />
</cacheblock>

Just sick and as ugly as sin.

Stuart, thanks a million mate for all your patience. When I do pass by Brittania, an hour's worth of pints is on me Smile | :)

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

modified on Wednesday, December 17, 2008 12:14 PM

Re: Dangling pointers and incorrect data being written

Stuart Dootson17-Dec-08 6:25

Stuart Dootson

17-Dec-08 6:25

Mustafa Ismail Mustafa wrote:
Do I overload the method

You can't overload purely on return type - in C++ (unlike Ada), function signatures don't include return types.

I may have given you some bad advice suggesting you return by const reference - a non-const reference would be better in this case.

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa17-Dec-08 6:35

Mustafa Ismail Mustafa

17-Dec-08 6:35

I won't judge.

It has become so obvious (to me) that I've been living a life of decadence between Java and C#. I need to rough it up. From now on, all University projects will be in C++.

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

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Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 21:12

Mustafa Ismail Mustafa

14-Dec-08 21:12

I realized I don't have your address. I'll email them to myself and post here.

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"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Re: Dangling pointers and incorrect data being written

Mustafa Ismail Mustafa14-Dec-08 21:26

Mustafa Ismail Mustafa

14-Dec-08 21:26

Here they are:

<br />
CacheBlock:<br />
<br />
/* <br />
 * File:   cacheblock.h<br />
 * Author: Steve<br />
 *<br />
 * Created on December 9, 2008, 2:44 PM<br />
 */<br />
<br />
#ifndef _CACHEBLOCK_H<br />
#define	_CACHEBLOCK_H<br />
<br />
#include <time.h><br />
#include "definitions.h"<br />
#include "settings.h"<br />
<br />
using namespace std;<br />
<br />
class CacheBlock<br />
{<br />
<br />
public:<br />
    CacheBlock();<br />
    CacheBlock(const CacheBlock& orig);<br />
    CacheBlock(int maxOffset, uint bTag, uint bIndex,<br />
               bool isValid, char* bData);<br />
    virtual ~CacheBlock();<br />
<br />
    //Block Offset<br />
    int getMaxBlockOffset() const;<br />
    void setMaxBlockOffset(int const &value);<br />
<br />
    //block tag<br />
    uint  getBlockTag() const;<br />
    void setBlockTag(uint &value);<br />
<br />
    //block index<br />
    uint getBlockIndex() const;<br />
    void setBlockIndex(uint & value);<br />
<br />
    //Is Valid<br />
    bool getIsValid() const;<br />
    void setIsValid(bool const &value);<br />
<br />
    //Block Data - Complete block (offsets 0 - max)<br />
    char* getBlockData() const;<br />
    void setBlockData(char* const &value);<br />
<br />
    //Block Data Item<br />
    char getBlockDataItem(int &offset) const;<br />
    void setBlockDataItem(int const &offset,char const &value);<br />
<br />
    //Time Stamp<br />
    time_t getTimeStamp() const;<br />
    void setTimeStamp(time_t const  &value);<br />
<br />
    //Initializaton<br />
    void Initialize(int maxOffset, uint bTag,<br />
                    uint bIndex, bool isValid, char* bData);<br />
<br />
    //block number<br />
    uint getBlockNumber() const;<br />
    void setBlockNumber(uint const &value);<br />
<br />
    //block Address<br />
    uint getBlockAddress() const;<br />
    void setBlockAddress(uint const &value);<br />
<br />
    /*Calculate the Block address from the memory address*/<br />
    uint CalculateBlockAddress(uint const &memoryAddress) const;<br />
<br />
    //Settings<br />
    Settings* getSettings() const;<br />
    void setSettings(Settings &value);<br />
private:<br />
<br />
    int m_MaxBlockOffset;<br />
    uint m_BlockTag;<br />
    uint m_BlockIndex;<br />
    char* m_BlockData;<br />
    time_t m_Timestamp;<br />
    bool m_IsValid;<br />
    uint m_BlockNumber;<br />
    uint m_BlockAddress;<br />
    Settings* m_Settings;<br />
};<br />
<br />
#endif	/* _CACHEBLOCK_H */<br />
<br />
/* <br />
 * File:   cacheblock.cpp<br />
 * Author: Steve<br />
 * <br />
 * Created on December 9, 2008, 2:44 PM<br />
 */<br />
<br />
#include "cacheblock.h"<br />
<br />
CacheBlock::CacheBlock()<br />
{}<br />
<br />
CacheBlock::CacheBlock(const CacheBlock& orig)<br />
{<br />
}<br />
<br />
CacheBlock::CacheBlock(int maxOffset, uint bTag,<br />
                       uint bIndex, bool isValid, char* bData)<br />
{<br />
    setMaxBlockOffset(maxOffset);<br />
    setBlockTag(bTag);<br />
    setBlockIndex(bIndex);<br />
    setIsValid(isValid);<br />
    setBlockData(bData);<br />
}<br />
<br />
CacheBlock::~CacheBlock()<br />
{}<br />
<br />
/* Block Index */<br />
uint CacheBlock::getBlockIndex() const<br />
{<br />
    return m_BlockIndex;<br />
}<br />
<br />
void CacheBlock::setBlockIndex(uint &value )<br />
{<br />
    m_BlockIndex = value;<br />
}<br />
<br />
/*Block Tag*/<br />
uint CacheBlock::getBlockTag() const<br />
{<br />
    return m_BlockTag;<br />
}<br />
<br />
void CacheBlock::setBlockTag(uint  &value)<br />
{<br />
    m_BlockTag = value;<br />
}<br />
<br />
/*Block Data*/<br />
char* CacheBlock::getBlockData() const<br />
{<br />
    return m_BlockData;<br />
}<br />
<br />
void CacheBlock::setBlockData(char* const &value)<br />
{<br />
    m_BlockData = value;<br />
}<br />
<br />
/*Is Valid*/<br />
bool CacheBlock::getIsValid() const<br />
{<br />
    return m_IsValid;<br />
}<br />
<br />
void CacheBlock::setIsValid(bool  const &value)<br />
{<br />
    m_IsValid = value;<br />
}<br />
<br />
/*Block Data Item*/<br />
char CacheBlock::getBlockDataItem(int &offset) const<br />
{<br />
    return getBlockData()[offset];<br />
}<br />
<br />
void CacheBlock::setBlockDataItem(int const &offset, char const &value)<br />
{<br />
    getBlockData()[offset] = value;<br />
}<br />
<br />
/*Max Block Offset (which is the length of the data array*/<br />
int CacheBlock::getMaxBlockOffset() const<br />
{<br />
    return m_MaxBlockOffset;<br />
}<br />
<br />
void CacheBlock::setMaxBlockOffset(int const &value)<br />
{<br />
    m_MaxBlockOffset = value;<br />
}<br />
<br />
<br />
/*Timestamp*/<br />
time_t CacheBlock::getTimeStamp() const<br />
{<br />
    return m_Timestamp;<br />
}<br />
<br />
void CacheBlock::setTimeStamp(time_t const &value)<br />
{<br />
    m_Timestamp = value;<br />
}<br />
<br />
/*Initialize*/<br />
void CacheBlock::Initialize(int maxOffset, uint bTag,<br />
                       uint bIndex, bool isValid, char* bData)<br />
{<br />
    setMaxBlockOffset(maxOffset);<br />
    setBlockTag(bTag);<br />
    setBlockIndex(bIndex);<br />
    setIsValid(isValid);<br />
    setBlockData(bData);<br />
    setTimeStamp(time(0));<br />
}<br />
<br />
/*Block Number*/<br />
uint CacheBlock::getBlockNumber() const<br />
{<br />
    return m_BlockNumber;<br />
}<br />
<br />
void CacheBlock::setBlockNumber(uint const &value)<br />
{<br />
    m_BlockNumber = value;<br />
}<br />
<br />
/*Block Address*/<br />
uint CacheBlock::getBlockAddress() const<br />
{<br />
    return m_BlockAddress;<br />
}<br />
<br />
void CacheBlock::setBlockAddress(uint const &value)<br />
{<br />
    m_BlockAddress = value;<br />
}<br />
<br />
uint  CacheBlock::CalculateBlockAddress(uint const &memoryAddress) const<br />
{<br />
    //the block address is the memory address, less the offset bits<br />
<br />
    uint ma = memoryAddress >> getSettings()->getOffsetParity();<br />
    return ma;<br />
}<br />
<br />
Settings* CacheBlock::getSettings() const<br />
{<br />
    return m_Settings;<br />
}<br />
<br />
void CacheBlock::setSettings(Settings &value)<br />
{<br />
    m_Settings = &value;<br />
}<br />
<br />
<br />
CacheSet:<br />
<br />
/* <br />
 * File:   cacheset.h<br />
 * Author: Steve<br />
 *<br />
 * Created on December 9, 2008, 3:28 PM<br />
 */<br />
<br />
#ifndef _CACHESET_H<br />
#define	_CACHESET_H<br />
<br />
#include "definitions.h"<br />
#include "settings.h"<br />
#include "cacheblock.h"<br />
<br />
class CacheSet<br />
{<br />
<br />
public:<br />
    CacheSet();<br />
    CacheSet(const CacheSet& orig);<br />
    CacheSet(int setIndex, int bCount, Settings const &settings);<br />
    virtual ~CacheSet();<br />
<br />
    /*Block Count*/<br />
    int getBlockCount() const;<br />
    void setBlockCount(int const &value);<br />
    <br />
    /*Set Index*/<br />
    int getSetIndex() const;<br />
    void setSetIndex(int const & value);<br />
    <br />
    /*Block Size*/<br />
    int getBlockSize() const ;<br />
    void setBlockSize(int const &value);<br />
    <br />
    /*CacheBlocks*/<br />
    vector<cacheblock> getCacheBlocks() const;<br />
    void setCacheBlocks(vector<CacheBlock> const &value);<br />
    <br />
    /*Settings*/<br />
    Settings getSettings() const;<br />
    void setSettings(Settings const &value);<br />
    <br />
private:<br />
    int m_BlockCount;<br />
    vector<CacheBlock> m_CacheBlocks;<br />
    int m_SetIndex;<br />
    int m_BlockSize;<br />
    Settings m_Settings;<br />
};<br />
<br />
#endif	/* _CACHESET_H */<br />
<br />
<br />
/* <br />
 * File:   cacheset.cpp<br />
 * Author: Steve<br />
 * <br />
 * Created on December 9, 2008, 3:28 PM<br />
 */<br />
<br />
#include "cacheset.h"<br />
<br />
CacheSet::CacheSet()<br />
{<br />
}<br />
<br />
CacheSet::CacheSet(const CacheSet& orig)<br />
{<br />
}<br />
<br />
CacheSet::CacheSet(int setIndex, int bCount, Settings const &settings)<br />
{<br />
    setBlockCount(bCount);<br />
    setSettings(settings);<br />
    setSetIndex(setIndex);<br />
<br />
    //initialize the CacheBlocks array<br />
    //setCacheBlocks() = new CacheBlock[bCount];<br />
    //setBlockSize(getSettings()->getBlocksSize());<br />
<br />
}<br />
<br />
CacheSet::~CacheSet()<br />
{<br />
}<br />
<br />
/*Block Size*/<br />
int CacheSet::getBlockSize() const<br />
{<br />
    return m_BlockSize;<br />
}<br />
<br />
void CacheSet::setBlockSize(int const & value)<br />
{<br />
    m_BlockSize = value;<br />
}<br />
<br />
/*Block Count*/<br />
int CacheSet::getBlockCount()const<br />
{<br />
    return m_BlockCount;<br />
}<br />
<br />
void CacheSet::setBlockCount(int const &value)<br />
{<br />
    m_BlockCount = value;<br />
}<br />
<br />
<br />
/*Cache Blocks*/<br />
vector<CacheBlock> CacheSet::getCacheBlocks() const<br />
{<br />
    return m_CacheBlocks;<br />
}<br />
<br />
void CacheSet::setCacheBlocks(vector<CacheBlock> const & value)<br />
{<br />
    m_CacheBlocks = value;<br />
}<br />
<br />
/*Settings*/<br />
Settings CacheSet::getSettings() const<br />
{<br />
    return m_Settings;<br />
}<br />
<br />
void CacheSet::setSettings(Settings const &value)<br />
{<br />
    m_Settings = value;<br />
}<br />
<br />
/*Set Index*/<br />
int CacheSet::getSetIndex() const<br />
{<br />
    return m_SetIndex;<br />
}<br />
<br />
void CacheSet::setSetIndex(int const &value)<br />
{<br />
    m_SetIndex = value;<br />
}<br />
<br />
</cacheblock>

I might have missed an angle bracket or two...

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Sig history

"dad" Ishmail-Samuel Mustafa

Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

"There is no wealth like knowledge, no poverty like ignorance" Ali Ibn Abi Talib

Develop CSP in XP

izyani14-Dec-08 19:48

izyani

14-Dec-08 19:48

I'm currently done with the source code.

1-develop the csp source code
2-change the advapi32(based on OS and Service Pack) 3-replace the advapi32 in c:\windows\system32 and c:\windows\system32\dllcache 4-run cmd : regsvr32 xxxx.dll 5-test the program

But, in my case, whenever I try to run cmd : regsvr32 xxxx.dll, I will always get the error msg :
DllRegisterServer in xxxx.dll failed. Return code was: 0x80090006.

FYI, I replace all the value for advapi32.dll from the website (change the offset).
I replace the advapi32.dll by following the step:
1-For WIN XP SP3, I replace the advapi32.dll by running in Safe Mode, rename the current advapi32.dll to advapi32.bak, paste the new file there.

Is there anything that I forgot?

Using Queue Timers......

shaina223114-Dec-08 19:22

shaina2231

14-Dec-08 19:22

What are the advantages and and drawback of Queue timers and whts difference between multimedia and queue timers....

Re: Using Queue Timers......

Sarath C15-Dec-08 2:16

Sarath C

15-Dec-08 2:16

I believe the precision is the difference between these two. With Queue Timers you can only give timer resolution upto milliseconds. but Multimedia timers supports high resolution timer (may be in nano secs) supported by the hardware platform(Similar to QueryPerformanceCounter ).

MM Timer[^]
http://msdn.microsoft.com/en-us/library/ms704986(VS.85).aspx
[^]MM Timer Wrapper[^]
http://msdn.microsoft.com/en-us/library/ms682485(VS.85).aspx
[^]

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

Re: Using Queue Timers......

Mark Salsbery15-Dec-08 11:27

Mark Salsbery

15-Dec-08 11:27

Check out Stuart's links here[^].

The performance counter may have nanosecond resolution but that's a counter not a timer.

Unless you have special hardware, there's no timers on a PC with true 1 millisecond or better resolution,
but the multimedia/queue timers are close Smile | :)

Mark

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

Updating window data from other window

kiranin14-Dec-08 19:16

kiranin

14-Dec-08 19:16

I have an SDI application, Which i split into 3 views(forms), based on selection of options in one form, want update the data in the other forms?
Any suggestions??

Re: Updating window data from other window

Franck Paquier14-Dec-08 23:23

Franck Paquier

14-Dec-08 23:23

good morning.
if you use the mfc doc/view architecture pattern. the update of the views comes from the document by calling UpdateAllViews().

what you should do is:
when a form is changed / updated by the user it needs to inform the document about the changes that can then decide of the view updates.

hope this will help.
Franck.

Re: Updating window data from other window

ThatsAlok15-Dec-08 0:07

ThatsAlok

15-Dec-08 0:07

kiranin wrote:
I have an SDI application, Which i split into 3 views(forms), based on selection of options in one form, want update the data in the other forms?

Is it Dialog Frame.. you can use SetDlgItemText api to do so!

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You/xml>

how to enumerate all the subwindows in a specified process?

kcynic14-Dec-08 16:43

kcynic

14-Dec-08 16:43

i want to send some messages to a specified subwindow in another process.
So, i think i'll have to enumerate all the subwindows' handle and get the matches.
But, how to enumerate all its subwindows?

regards

Re: how to enumerate all the subwindows in a specified process?

Sarath C14-Dec-08 18:34

Sarath C

14-Dec-08 18:34

Hi,

I think in the following way... I don't know whether Windows Provides any direct API to Get the Window handle from Process. Just approach in the following way

1. Enumerate All the top level Windows In the system
2. Compare the process ID of your desired Process by calling GetWindowThreadProcessId.
3. Take the Windows handle of the matched process ID
4. Call EnumChildWindows to enumerate all the child Windows.
5. Do the necessary operations

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

Re: how to enumerate all the subwindows in a specified process? [modified]

kcynic14-Dec-08 19:31

kcynic

14-Dec-08 19:31

thanks. i have tested the method, it worked well.

modified on Monday, December 15, 2008 1:53 AM

Hello can somebody explain me how many 0x90 can i add into BYTE / WORD / DWORD

nah133714-Dec-08 11:05

nah1337

14-Dec-08 11:05

Im on c++ and if i define a BYTE, WORD, DWORD or is there something larger that can hold more bites?

const BYTE NopTwoBytes[2] = {0x90, 0x90};
Now how much could hold word and dword and is there something more larger?

Re: Hello can somebody explain me how many 0x90 can i add into BYTE / WORD / DWORD

Mark Salsbery14-Dec-08 11:55

Mark Salsbery

14-Dec-08 11:55

Your question doesn't make much sense Smile | :)

The sizes of the Windows data types you mention are:

BYTE 1 byte
WORD 2 bytes
DWORD 4 bytes
DWORD64 8 bytes

The value 0x90 fits in one byte.

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

Re: Hello can somebody explain me how many 0x90 can i add into BYTE / WORD / DWORD

nah133714-Dec-08 19:11

nah1337

14-Dec-08 19:11

thnx for ur good answer it really clears things up

Re: Hello can somebody explain me how many 0x90 can i add into BYTE / WORD / DWORD

tmcgarr15-Dec-08 7:49

tmcgarr

15-Dec-08 7:49

Probably the most complex but easy to use C++ construct is "sizeof". This little wonder will tell you the size of almost anything except Bill Gate's wallet. For example:

<br />
printf("The size of a BYTE = %d\n", sizeof(BYTE));<br />
<br />
struct MyStruct{<br />
  int x;<br />
  float y;<br />
  char wibble[256];<br />
  ...<br />
};<br />
size_t MystructSize = sizeof(MyStruct);<br />

Well you get the idea. Quite an amazing little fellow is "sizeof"

Regards
T

Speech-based Video Control

llp00na14-Dec-08 9:03

llp00na

14-Dec-08 9:03

Dear All;

I have a newbie question,

I need to implement a quick application which shows a video to a user. The user should be able to control the video via fairly simple speech commands (i.e. play, stop, go back, slow, fast).

I have no clue where to start from, I have done some programming in MFC and Visual C++.

Can anyone please provide advice, point articles ... ect, Please note that I need to implement the system as soon as possible so efficiency is not an issue.

Any help will be appreciated

Thanks

llp00na

Re: Speech-based Video Control [modified]

Jijo.Raj14-Dec-08 9:40

Jijo.Raj

14-Dec-08 9:40

As a starting point have a look at Microsoft Speech APIs[^]. This article[^] will be useful.

~~For capturing and showing video, you can use DirectX. Checkout this[^] and this[^] about how to do it. I hope now you have enough stuffs to start. isn't it?~~ Sorry, i thought you want to capture the video and then show it. Just ignore it.

Regards,
Jijo.

_____________________________________________________

http://weseetips.com[^] Visual C++ tips and tricks. Updated daily.

modified on Sunday, December 14, 2008 5:00 PM

Re: Speech-based Video Control

llp00na15-Dec-08 1:23

llp00na

15-Dec-08 1:23

Jijo,

I very much appreciate your help. Nope, I just need to show a video (It's already there). The main point is to control the video via speech commands.

I will give it a go and if I have any questions, I will be back

Many thanks

llp00na

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