C / C++ / MFC

24-Sep-04 3:33

I posted a couple of questions yesterday about a BYTE array created on the heap. After creating it I use SafeArrayAccessData() and SafeArrayUnAccessData() after puttin the info in the array. This is the exact same method I've seen used in countless examples when I googled this stuff. However, I was getting a memory leak because I didn't call 'delete' on the pointer. When I tried to call delete on the pointer, my program ASSERTed in _CrtIsValidHeapPointer(). I never wrote to the array after that and can't figure out why it's doing that, so here's what I did:

UINT nAddress = 0;
BYTE* pBuf = NULL;

//some other stuff

pBuf = new BYTE[nLength];
nAddress = (UINT)pBuf;  //to hold initial address.

//continue with code, and catch handler

if(nAddress)
{
    pBuf = (BYTE*)nAddress;
    delete [] pBuf;
    pBuf = NULL;
}

It's been working so far, and not MEMORY LEAKS, but...
Is this okay?

[insert witty comment here]

bdiamond Sleepy | :zzz:

Antony M Kancidrowski24-Sep-04 3:58

Antony M Kancidrowski

24-Sep-04 3:58

I would tend to ensure that the pBuf pointer is never moved from the start of the array and always delete it.

BYTE* pBuf = NULL;
pBuf = new BYTE[nLength];

BYTE* pTemp = pBuf;
// Do something using pTemp rather than pBuf

delete [] pBuf;
pBuf = NULL;

Hope I have not misunderstood your intensions.

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

BlackDice24-Sep-04 4:12

24-Sep-04 4:12

actually, it's already doing that in the code I omitted. There's another variable called pBytes that I use, but I was still getting that ASSERT.

[insert witty comment here]

bdiamond Sleepy | :zzz:

Antony M Kancidrowski24-Sep-04 4:37

Antony M Kancidrowski

24-Sep-04 4:37

Um strange. If pBuf doesn't become corrupted then you should not have an ASSERT.

I would tend to alter the code back to how you had it and step through with the debugger watching the value of pBuf.

I guess you are masking a bigger problem here!

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

David Crow24-Sep-04 4:42

24-Sep-04 4:42

Antony M Kancidrowski wrote:
I guess you are masking a bigger problem here!

Agreed.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

BlackDice24-Sep-04 4:57

24-Sep-04 4:57

Okay I put the code back how it was (good thing I'm using SourceSafe). When stepping through the code, this is what happened. After stepping through the line where the pointer is allocated (see line 1) the value in the watch window is
0x01970190 "ÍÍÍÍÍÍÍÍÍÍÍ" unsigned char *
after stepping through line 2 the value is:
0x0018f760 "ÐÏà¡±á" unsigned char *

here are the lines:

Line 1: pBuf = new BYTE[nLength];
Line 2: SafeArrayAccessData(varBLOB.parray,(void **)&pBuf);

Also, I see the type is listed as 'unsigned char*' in both, and pBuf is declared like this:

BYTE* pBuf;

[insert witty comment here]

bdiamond Sleepy | :zzz:

David Crow24-Sep-04 5:02

24-Sep-04 5:02

When using SafeArrayAccessData(), there is no need to allocate memory for the second parameter.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

RESOLVED

BlackDice24-Sep-04 5:10

24-Sep-04 5:10

As always you're exactly right. I removed the 'new' allocation from my code and it works just fine, and no memory leaks!! Thanks for the millionth time.

[insert witty comment here]

bdiamond Sleepy | :zzz:

David Crow24-Sep-04 4:34

24-Sep-04 4:34

bdiamond wrote:
...my program ASSERTed in _CrtIsValidHeapPointer().

What line of what file?

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

BlackDice24-Sep-04 4:43

how to merge cell in word by VC

24-Sep-04 4:43

when i tried to 'delete pBuf' it asserted in "dbgheap.c" in the above-mentioned function. Now when I trie to recreate it using 'delete [] pBuf', it crashes in "compip.h" on line 303 in this code:

~_com_ptr_t() throw()
{ 
    _Release(); 
}

[insert witty comment here]

bdiamond Sleepy | :zzz:

yingkou24-Sep-04 2:41

yingkou

24-Sep-04 2:41

I want to merge cell of the word by VC and my codes as follow:
for(int i=3,j=0;j{
c1.ReleaseDispatch();
c2.ReleaseDispatch();
c1=pTable->Cell(i,1);
c2=pTable->Cell(i+DayCount,1);
c1.Merge(c2);
}
the first time this section codes work well, but the second time bug happened.
and if I merge the first row in the seconde time and don't merge the first column it works well too.and continuiously merge the first column buf happned too,why?

Detect default language 'en' or 'de'

Moak24-Sep-04 2:29

Moak

24-Sep-04 2:29

Hi,

how do I detect users's default language in something like 'en' or 'de' or 'en-us'? There is GetUserDefaultUILanguage() but i don't know how to convert into a RFC3066 style text representation. Also I am having difficulties to detect if user has per default 12 or 24 hours format selected.

Thanks for help.

Re: Detect default language 'en' or 'de'

Antony M Kancidrowski24-Sep-04 3:25

Antony M Kancidrowski

24-Sep-04 3:25

Have you tried GetLocaleInfo().

Call the function with LCTYPE set to:

LOCALE_ILANGUAGE - IIRC gets the language identifier.
LOCALE_ITIME - Will get 12 / 24 hr format

to get the appropriate information.

Ant.

I'm hard, yet soft.
I'm coloured, yet clear.
I'm fruity and sweet.
I'm jelly, what am I? Muse on it further, I shall return! - David Williams (Little Britain)

Re: Detect default language 'en' or 'de'

Moak24-Sep-04 3:43

Moak

24-Sep-04 3:43

ah lots of good stuff there, I'll try that.

Thanks!

Get / Set Windows Title Bar Font, Text Colour and Size

Tristan Rhodes24-Sep-04 2:26

Tristan Rhodes

24-Sep-04 2:26

I'm really struggling to find anything that would enable me to do this. It's driving me crazy, as i know everything about the title bar now, except this.

I'm looking for the kind of options got in NT Display>Appearance tab where the title bar Item has the option to set a variety of properties, including font, colour, etc.

I get the size of it, and the size of the icon, but the one thing I can't do is the size / font / color of the text.

Anyone got any ideas?

Cheers

Cata

Re: Get / Set Windows Title Bar Font, Text Colour and Size

Ravi Bhavnani24-Sep-04 3:17

Ravi Bhavnani

24-Sep-04 3:17

SystemParamtersInfo (SPI_GETNONCLIENTMETRICS);

/ravi

My new year's resolution: 2048 x 1536
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Re: Get / Set Windows Title Bar Font, Text Colour and Size

Tristan Rhodes24-Sep-04 4:25

Tristan Rhodes

24-Sep-04 4:25

Interesting. This method is completely undocumented in MSDN.

Can you tell me which DLL it's in? And where I can find a list of related Enums + structs?

Cheers

Cata

Re: Get / Set Windows Title Bar Font, Text Colour and Size

David Crow24-Sep-04 4:39