Scope Error - C / C++ / MFC Discussion Boards

Rage26-May-03 2:16

26-May-03 2:16

I suppose DSBLOCK_ENTIREBUFFER is equal to 0, since you are giving 0 as last parameter of your function. If not, then this will attempt to lock a buffer which can have any size, since m_dwBufferBytes is not initialised, causing the lock to fail randomly.

~RaGE();

Re: DirectSound Buffer->Lock Error

Miepmuts26-May-03 2:54

Miepmuts

26-May-03 2:54

It's not a random error but every time the same one: DSERR_PRIOLEVELNEEDED

Even when I fill in those two variables the function returns the same error.
It is a very strange error. I asked someone at my work, and even he didn't see a solution.

Re: DirectSound Buffer->Lock Error

Rage26-May-03 3:44

Rage

26-May-03 3:44

It must be something you are doing inbetween the code lines you have posted.

~RaGE();

Re: DirectSound Buffer->Lock Error

Miepmuts26-May-03 4:15

Miepmuts

26-May-03 4:15

Allright then. Here it goes:

<br />
hr = DirectSoundCreate(NULL, &m_pDS, 0);<br />
if(hr == DS_OK)<br />
{<br />
  HWND MainhWnd;<br />
  MainhWnd = GetSafeHwnd();<br />
  hr = m_pDS->SetCooperativeLevel(MainhWnd, DSSCL_NORMAL);<br />
  if(hr == DS_OK)<br />
  {<br />
    //Create Primary audio 3D Buffer<br />
    DSBUFFERDESC bufferDesc;<br />
    memset(&bufferDesc, 0, sizeof(DSBUFFERDESC));<br />
    bufferDesc.dwSize = sizeof(DSBUFFERDESC);<br />
    bufferDesc.dwFlags = DSBCAPS_PRIMARYBUFFER | DSBCAPS_GETCURRENTPOSITION2 ;<br />
    bufferDesc.dwBufferBytes = 0;<br />
    bufferDesc.lpwfxFormat = NULL;<br />
    hr = m_pDS->CreateSoundBuffer(&bufferDesc, &m_pPrimaryBuffer, NULL);<br />
    if(hr == DS_OK)<br />
    {<br />
	hr = m_pPrimaryBuffer->QueryInterface( IID_IDirectSound3DBuffer, (void**)    &m_pDS3DBuffer );<br />
	//Set primary internal extended format<br />
	WAVEFORMATEXTENSIBLE formatex;<br />
	memset(&formatex, 0, sizeof(WAVEFORMATEXTENSIBLE));<br />
	formatex.Format.wFormatTag = WAVE_FORMAT_EXTENSIBLE;<br />
	formatex.Format.nChannels = 4;<br />
	formatex.Format.nSamplesPerSec = 44100;<br />
	formatex.Format.nAvgBytesPerSec = 352800;<br />
	formatex.Format.nBlockAlign = 8;<br />
	formatex.Format.wBitsPerSample = 16;<br />
	formatex.Format.cbSize = 22;<br />
	formatex.Samples.wValidBitsPerSample = 16;<br />
	formatex.dwChannelMask = SPEAKER_FRONT_LEFT | SPEAKER_FRONT_RIGHT<br />
				 | SPEAKER_BACK_LEFT | SPEAKER_BACK_RIGHT;<br />
	formatex.SubFormat = KSDATAFORMAT_SUBTYPE_PCM;<br />
	//Now create a normal sound buffer<br />
	DSBUFFERDESC bufferSec;<br />
	memset(&bufferSec, 0, sizeof(bufferSec));<br />
	bufferSec.dwSize = sizeof(bufferSec);<br />
	bufferSec.dwFlags = DSBCAPS_GETCURRENTPOSITION2;<br />
	bufferSec.lpwfxFormat = &waveformat;<br />
	hr = m_pDS->CreateSoundBuffer(&bufferDesc, &m_pDSBuffer, NULL);<br />
    }<br />
}<br />
<br />
HRESULT hr;<br />
BYTE* pbWavData;<br />
UINT cbWavSize;<br />
VOID* pbData = NULL;<br />
VOID* pbData2 = NULL;<br />
DWORD dwLength;<br />
DWORD dwLength2;<br />
<br />
int nWaveFileSize = ckIn.cksize;<br />
pbWavData = new BYTE[nWaveFileSize];<br />
if(pbWavData == NULL)<br />
{<br />
    return 0;<br />
}<br />
MMIOINFO mmioinfoIn;<br />
<br />
cbWavSize = 0;<br />
if(mmioGetInfo(hmmioIn, &mmioinfoIn, 0) != 0)<br />
{<br />
    return 0;<br />
}<br />
UINT cbDataIn = nWaveFileSize;<br />
if(cbDataIn > ckIn.cksize)<br />
{<br />
    cbDataIn = ckIn.cksize;<br />
}<br />
ckIn.cksize -= cbDataIn;<br />
	<br />
for(DWORD ct = 0; ct < cbDataIn; ct++)<br />
{<br />
    if(mmioinfoIn.pchNext == mmioinfoIn.pchEndRead)<br />
    {<br />
	if(mmioAdvance(hmmioIn, &mmioinfoIn, MMIO_READ) != 0)<br />
	{<br />
	    return 0;<br />
	}<br />
	if(mmioinfoIn.pchNext == mmioinfoIn.pchEndRead)<br />
	{<br />
	    return 0;<br />
	}<br />
    }<br />
<br />
    *((BYTE*)pbWavData + ct) = *((BYTE*)mmioinfoIn.pchNext);<br />
    mmioinfoIn.pchNext++;<br />
}<br />
if(mmioSetInfo(hmmioIn, &mmioinfoIn, 0) != 0)<br />
{<br />
    return 0;<br />
}<br />
cbWavSize = cbDataIn;<br />
m_dwBufferBytes = 8 * 1024;<br />
<br />
StartDataRead(&m_ckIn);<br />
int lPos=0;<br />
hr= m_pDSBuffer->Lock(lPos, m_dwBufferBytes, &pbData, &dwLength, &pbData2,&dwLength2,    DSBLOCK_ENTIREBUFFER);<br />
if( hr != DS_OK)  //hr returns a strange number which equals to DSERR_PRIOLEVELNEEDED<br />
{<br />
   return 0;<br />
}<br />
<br />
memcpy(pbData, pbWavData, m_dwBufferBytes);<br />
m_pDSBuffer->Unlock(pbData, m_dwBufferBytes, NULL, 0);<br />
pbData = NULL;<br />
return 1;<br />
<br />

I hope you can do something with this. There is a part of code in between of initialising the mmio and the chunks.

GCC with MCVC IDE

Andrew Walker26-May-03 1:24

Andrew Walker

26-May-03 1:24

Is it possible to run GCC within Microsoft's IDE (6 or .NET, it doesn't matter which), I just want to test some template code.

I know that it is possible because comeau and the intel compiler do it, but has anyone seen it for GCC.

Cool | :cool:

thanks

Re: GCC with MCVC IDE

tareqsiraj26-May-03 9:42

tareqsiraj

26-May-03 9:42

Try the following links. Smile | :)

http://sources.redhat.com/ml/crossgcc/2001-05/msg00046.html
http://www.cygwin.com/ml/crossgcc/2001-09/msg00069.html

-Tareq

VC 5 <-> VC6

JensB26-May-03 0:04

JensB

26-May-03 0:04

Hello

Does anyone know a url where i can find an extensively comparison between Visual C++ 5.0 and the 6.0 version? Like for example: 6.0 version had this as advantage, this as disadvantage etc

Greetings
Jens

Scope Error

Paul Hooper25-May-03 23:45

Paul Hooper

25-May-03 23:45

I just spent the best part of today finding a nasty little bug and thought I might "share" with you.

We had some code that basically went

{<br />
   CPen apen;<br />
   apen.CreatePen(...);<br />
   dc->SelectObject(&apen);<br />
<br />
   //Do lots of work with dc<br />
<br />
   dc->SelectStockObject(BLACK_PEN);  //Select apen out so it can clean up<br />
}

Last version, the code was changed to something like

{<br />
   if (option)<br />
   {<br />
      CPen apen;<br />
      apen.CreatePen(...);<br />
      dc->SelectObject(&apen);<br />
<br />
      //Do lots of work with dc<br />
   }<br />
   else<br />
   {<br />
      CPen bpen;<br />
      bpen.CreatePen(...);<br />
      dc->SelectObject(&bpen);<br />
<br />
      //Do lots of work with dc<br />
   }<br />
   dc->SelectStockObject(BLACK_PEN);  //Select pens out so they can clean up<br />
}

I am sure you can see the error... apen and bpen are now being destroyed before selected out. Resource leak.

Running this code on Win2000/XP is fine because they clean up the mess. Running on 95,98,ME caused massive resource leaks (obviously!) The error is obvious when simplified as above but it was not the least bit obvious in the production code.

It's always the simple things that bite you!

Paul Hooper

If you spend your whole life looking over your shoulder, they will get you from the front instead.

Re: Scope Error

John R. Shaw26-May-03 9:51

John R. Shaw

26-May-03 9:51

CPen* pOldPen = dc->SelectObject(&apen);
//Do lots of work with dc
dc->SelectObject(pOldPen);

or you could just use SaveDC() and RestoreDC() so you do not have to keep track of what objects are selected.

int nSavedDC = dc->SaveDC();
dc->SelectObject(&apen);
//Do lots of work with dc
dc->RestoreDC(nSavedDC);

Trust in the code Luke. Yea right!

Re: Scope Error

John R. Shaw26-May-03 10:04

John R. Shaw

26-May-03 10:04

Oh! One more thing, do not do this:

if(..)
{
    CPen apen;
    ....
    dc->SelectObject(&apen);
    //Do lots of work with dc
}

Unless you are going to restore the old pen before leaving the 'if' block, because (of course) apen goes out of scope as soon as you leave the block.

CPen apen;
if(..)
{
    ....
    dc->SelectObject(&apen);
    //Do lots of work with dc
}

Also it you must use CPen::CreatePen(), instead of the constructor, to create your pens then you must call CPen::DeleteObject() to destroy it or you will get memory leaks.

Trust in the code Luke. Yea right!

Communication problem between dialog window and frame window

chen25-May-03 23:38

chen

25-May-03 23:38

Hi,

In a dialog based application (main application window), a frame window
can be drived by click a menu item. Now my problem is that i want use some functions defined at the appDlg.cpp, how should i call these functions in myframe.cpp? How the communications are constructed ?

Thanks in advance!

chen

Re: Communication problem between dialog window and frame window

Rage25-May-03 23:52

Rage

25-May-03 23:52

Three solutions :

1. Use user defined messages with SendMessage or PostMessage.

2. Overwrite the Create (Or DoModal) function of the frame window to add a pointer to a CYourDialog (where CYourDialog is the name of your dialog) as parameter. Put a member variable m_pMainDlg in your Frame window class, and store the pointer in it. Call your base class functions with

m_pMainDlg->Function1();

3.[MFC] Use AfxGetMainWnd() in a type cast :

CYourDialog *m_pMainDialog = (CYourDialog*)AfxgetMainWnd();
m_pMainDlg->Function1();

~RaGE();

How Do I Drag&Drop an ActiveX Control

ccdai25-May-03 23:11

ccdai

25-May-03 23:11

Hello....

I am having problems when I am trying to drag and drop one of my activeX control from an application to MS-WORD.

The problem is that I am not sure what format it is for an ActiveX Control in clipboard (ie. CF_TEXT is for text) so I dont know what to put as the first parameter in the function when I need to cashe my data into the global memory created ....

"opOleDataSource->CacheGlobalData(??????, hGlobal);"

Does anyone knows how to do this and Please advise me !!

Thank You !! Smile | :)

Parsing in C

Rickard Andersson²⁰25-May-03 22:57

Rickard Andersson²⁰

25-May-03 22:57

I have some problems with my code here. You can see where the error appears in the code:

char szCommand[] = "luc 192.168.244.151 5000 50 mypass";

void HotIceParser(const char* command, PHIPD phipd)
{
	char buffert[20+1] = {0};
	char* p1 = NULL;
	char* p2 = NULL;

#ifdef DEBUG_MODE
	assert(phipd != NULL);
#endif
	
	p1 = &buffert[0];
	p2 = &command[0];

	while((*p2 != ' ') && (*p2 != '\0'))
		*p1++ = *p2++;

	MessageBox(NULL, buffert, "1",MB_OK);

	if(strcmp(buffert,"luc") == 0)
	{
		phipd->type = LUC;
		p1 = &buffert[0];
		p2++;
		while((*p2 != ' ') && (*p2 != '\0'))
			*p1++ = *p2++;

		MessageBox(NULL, buffert, "2",MB_OK); // STACK AROUND buffert IS CORRUPTED!!! WHY??
		strcpy(phipd->luc.pszIP, buffert);
	}
}

Can you help me to solve this?

Rickard Andersson⁸
Here is my card, contact me later!
UIN: 50302279
E-Mail: nikado@pc.nu
Interests: C++, ADO, SQL, Winsock, 0s and 1s

Re: Parsing in C

jhwurmbach25-May-03 23:26

jhwurmbach

25-May-03 23:26

Do you really NEED to use C? Your line
char buffert[20+1] = {0};
seems to be C++ to me: I C, you would use zeromem() or memset().

But if using plain, ugly C is not of prime importance, because you use a C++-compiler anyway, you can just as well use std::string to do the parsing:

void HotIceParser(const char* cmd, PHIPD phipd)

std::string command( cmd );
std::string::iterator p1 = command.find_first_not_of(' \0');

..and so on..

My opinions may have changed, but not the fact that I am right.

Re: Parsing in C

Rickard Andersson²⁰26-May-03 0:24

Rickard Andersson²⁰

26-May-03 0:24

jhwurmbach wrote:
Do you really NEED to use C

Hm... in fact no. But I want to learn it.

jhwurmbach wrote:
char buffert[20+1] = {0};
seems to be C++ to me:

I C, you would use zeromem() or memset().

Thanks! Smile | :)

I want perfect C code!

Rickard Andersson⁸
Here is my card, contact me later!
UIN: 50302279
E-Mail: nikado@pc.nu
Interests: C++, ADO, SQL, Winsock, 0s and 1s

Re: Parsing in C

John R. Shaw26-May-03 10:13

John R. Shaw

26-May-03 10:13

char buffert[20+1] = {0};

This is C. When you initialise a buffer like this the buffer is initialised to all zeros.

char buffert[20+1] = {'\0'};
or
char buffert[20+1] = {(char)0};
is more correct.

char buffer[4] = {'1'} produces a buffer containing the follwing:

'1','\0','\0','\0'

Trust in the code Luke. Yea right!

Re: Parsing in C

Paul Hooper25-May-03 23:29

Paul Hooper

25-May-03 23:29

I am presuming that you are sending szCommand to the function. szCommand is longer than 20 characters and buffert will only hold 20. Your while loop will keep filling buffert past the 21 limit of your array and corrupt whatever is around.

You need to check that your command parameter is not bigger than buffert.

Paul Hooper

If you spend your whole life looking over your shoulder, they will get you from the front instead.

Re: Parsing in C

Rickard Andersson²⁰26-May-03 0:30

Rickard Andersson²⁰

26-May-03 0:30

Paul Hooper wrote:
I am presuming that you are sending szCommand to the function

Yes.

Paul Hooper wrote:
szCommand is longer than 20 characters and buffert will only hold 20.

Yes, but it's strange when Rage could get it to work... and me too... Unsure | :~

Paul Hooper wrote:
You need to check that your command parameter is not bigger than buffert.

Thanks!

Rickard Andersson⁸
Here is my card, contact me later!
UIN: 50302279
E-Mail: nikado@pc.nu
Interests: C++, ADO, SQL, Winsock, 0s and 1s

Re: Parsing in C

Paul Hooper26-May-03 1:51

Paul Hooper

26-May-03 1:51

Rickard Andersson18 wrote:
Yes, but it's strange when Rage could get it to work... and me too...

Not strange at all. Once you overrun a buffer ANYTHING is possible - depending on what has been overwritten. Anywhere from complete system compromise, pain, suffering, earthquakes, volcanoes (oops getting a little carried away) to ... absolutely nothing. These are really nasty faults BECAUSE the results can be variable. Just ask Microsoft!

Paul Hooper

If you spend your whole life looking over your shoulder, they will get you from the front instead.

Re: Parsing in C

Rage25-May-03 23:46

Rage

25-May-03 23:46

i have tried it out, and it works perfectly.

Only changed

char* p2 = NULL;

const char* p2 = NULL;

~RaGE();

Re: Parsing in C

Rickard Andersson²⁰26-May-03 0:32

Rickard Andersson²⁰

26-May-03 0:32

Yeah, I've tried it also now and it worked... strange!

Rickard Andersson⁸
Here is my card, contact me later!
UIN: 50302279
E-Mail: nikado@pc.nu
Interests: C++, ADO, SQL, Winsock, 0s and 1s

Re: Parsing in C

Ryan Binns26-May-03 1:46

Ryan Binns

26-May-03 1:46

You don't appear to be null-terminating buffert. Just before the MessageBox() call, do a *p1 = 0. AFAIK, your initialiser only sets the first location of the array to 0 - all the rest are left uninitialised.

Also, make sure that your buffert array is not being overrun - your code as written is a big security hole. What if somebody managed to send 22 characters without a space? If you're lucky it would crash. If not, who knows what data might get corrupted...

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Re: Parsing in C

jhwurmbach26-May-03 2:19

jhwurmbach

26-May-03 2:19

Ryan Binns wrote:
AFAIK, your initialiser only sets the first location of the array to 0 - all the rest are left uninitialised.

AFAIK the ={0}; does the same as zeromem() does - only that it is more pleasant to the eye. Wink | ;)

My opinions may have changed, but not the fact that I am right.

Re: Parsing in C

Ryan Binns26-May-03 2:22

Ryan Binns

26-May-03 2:22

Fair enough. I'll remember that Smile | :)

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

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