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Hi Chris,
If you look under the hood, you'll see that for Release MFC/MSVCRT that
new calls malloc() and delete calls free().
For Debug MFC and MSVCRT all calls to malloc() and free() actually go to malloc_dbg()
and free_dbg(). Since malloc and malloc_dbg() are exported functions they are only accessible via the jump table in the IAT of your DLL that is linked to MFC42uD.DLL (or MFC42D.DLL if you are MBCS). The import library will indicate that it wants MFC42uD.DLL or MFC42.DLL and will not resolve to the incorrect DLL (ie if it wants the release on it won't link against the debug one).
So that being the case it is pretty hard to call the release malloc() if you know you linked against the debug malloc(). If you want to try, put a breakpoint on a call to
new/malloc or free/delete and drop into assembly level and walk the calls, you can
tell very quickly if you ended up in the release or debug dll (for a start the source code only comes up in the debug dll as there is no debug info in the release dll to main to the release CRT source code that MFC ship.).
You should also note that many big name tools, such as Purify, will report that your program is using both MSVCRTD.DLL and MSVCRT.DLL at the same time. Why do they do this?
Your program is debug, so that explains MSVCRTD.DLL. Their program (the one that has
been injected into your program to inspect it) is almost certainly release code(*),
which explains MSVCRT.DLL. So why would they do that? The reason is that:-
a) Microsoft forbids the redistribution of DEBUG dlls.
b) The performance gains of using the release DLLs and the knowledge that an ASSERT
(that may just be a warning, not a genuine problem) can't come up.
As long as their program never mixes its calls up and always calls its MSVCRT.DLL
then it will be OK. So there are occasions when it is OK, but as other posters here
have noted, usually it is NOT ok.
It sounds like the 3rd party dll may be incorrectly assuming any memory that is passed to it to manage is always 'release mode' (for want of a better term) memory. In that case you are out of luck.
The memory management for DEBUG is pretty straightforward. The source code is in the MFC directory and implements its own linked list manager with a lot of overhead to
allow you to track it. It grabs larger chunks using HeapAlloc on a private heap.
The Release memory management consists of a small block heap, implemented in a way
that will not map in any way to the DEBUG memory management. For larger blocks
(greater than the value returned by sbh_get_threshold(), typically 0x03f8) the release
manager goes to HeapAlloc() in a private heap. Consult sbheap.c and winheap.c for
more details.
Hope this is some use. Any chance of naming the vendor/dll?
Stephen Kellett
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I disagree. It's quite easy to call the wrong malloc or free. For instance, if you are in debug, and you link to a release DLL. If that DLL allocates memory and returns it to your debug application, and your debug application frees that memory itself, you get major problems.
Another problem, especially with MFC, is that the size of objects can change between debug and release, thus if you allocate an object in release, but use it debug, it's going to assume a different memory layout. You might be using something like Stingray's ObjectiveToolkit, that implements it's own MFC derived classes in a DLL, for instance. In debug, the objects include dump information and additional functions. This can cause page faults or other nasty problems.
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Well we are both agreed on the fact that you shouldn't mix and
match the memory. The extra functions and data members you
refer to will also cause data offsets and possibly the virtual
function table to be at a different location than expected.
Defintely bad news.
If you intentionally link a release DLL to a debug DLL of course
the user will get problems if they mix and match the objects and
code.
The reason for my post was to point out that if you link against the DEBUG DLL you won't accidentally be calling the functions in
the release DLL, even if that release DLL is in the process. You have to go out of your way to link the wrong DLL, and in that case, well, you need to change your link options.
I have a project at present which intentionally loads the Release MSVCRT.DLL into a running program, be that program debug or release. It doesn't crash the running program because the only
code calling the release MSVCRT DLL is the code I injected into
the program. In the case that the running program is Release then
we both share the MSVCRT.DLL heap, which is allowed for in the design of MSVCRT.DLL as long as you are using the DLL and not linking statically.
Stephen Kellett
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I have a large custom database that I'd like to search for keywords. Anyone know of anything I could use that is ultra-fast?
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you need to scan the files and build an index(s) of the keywords ... like a web search engine ... then finding keywords is a snap
suggest you build a file of the keywords you want to define or a file of non-keywords you want to ignore and then use that to build the index of the stuff in the db
"every year we invent better idiot proof systems and every year they invent better idiots"
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what is the difference betweeen delete
and delete []
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If you allocate an array with new, you use delete [] when you free the memory.
--Mike--
http://home.inreach.com/mdunn/
This must be Thursday. I never could get the hang of Thursdays...
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But delete and delete[] both seem to generate the same assembly output, so is there really a difference ? 
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They may look the same, but they're not.
For instance, take this simple application:
#include "stdafx.h"
#include <iostream>
using namespace std;
class a
{
public:
a(){};
~a(){cout << "a::~a()\n";};
};
int main(int argc, char* argv[])
{
a *pa = new a[10];
delete [] pa;
cout << "------" << endl;
pa = new a[10];
delete pa;
return 0;
}
If your theory were correct, it would output 10 a::~a()'s followed by dashes and 10 more. Instead, this is the output:
a::~a()
a::~a()
a::~a()
a::~a()
a::~a()
a::~a()
a::~a()
a::~a()
a::~a()
a::~a()
------
a::~a()
As you can see, the destructor gets called 10 times when using delete [] and only once when using delete.
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Delete[] is necessary for deletion of objects. I mean instances of classes.
Objects in array should be garanteed to destruct itself and free resource.
Delete[] calls all of destructor of objects in array and call of destructor
calls destructor of base class's destructor.
So delete[] gaurantees destruction of all object in array .
For primitive types like int, long, char etc..
You don't have use delete[] for freeing resource.
Delete is enough. But this is only the theory..
In practice,I recommend to use delete[] whenever you're freeing resource in array.
Cause it makes code more clear and readable.
It looks to clear to other developers who are seeing your code or youself in future.
Regards,
Ryan
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Okay, this is kinda weird ...
I'm going to simplify it (but still show problem)
=================================================
char *ModuleList[10];
char *strInput;
char buffer[80] = {80};
bool bDone = false;
int iLoop = 0;
while (!bDone)
{
strInput = _cgets(buffer);
if (strcmp(strInput, "exit") == 0) { bDone = true; }
else
{
ModuleList[iLoop] = strInput;
iLoop++;
}
}
Now yeah iLoop will go higher than 9 that will cause an error .. but the problem is that the ModuleList array does this:
Input: test
ModuleList[0] == test;
ModuleList[1] == "";
..
Input: again
ModuleList[0] == "again";
ModuleList[1] == "again";
ModuleList[2] == ""
..
See what I mean? why does it change the previous values in the array instead of leaving them alone? The array seems to get screwed up when the strInput = _cgets(buffer); line gets called.
Any help here is much appreciated .. probably some stupid mistake, but I'm a little lost here
Thanks, Travis
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strInput is always has the same value (buffer+2). so, you are setting the same pointer value into each ModuleList element.
-c
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also the line char buffer[80] = {80}; should read char buffer[82] = {80};
just a small point
"every year we invent better idiot proof systems and every year they invent better idiots"
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Where you have:
char *ModuleList[10];
it is NOT an array of strings!!
It is actuall an array of string pointers.
So where you go:
ModuleList[iLoop] = strInput;
what you actually doing is setting all of the string pointers in the array to
point to the same string. The same string that you change every time around
the loop.
So if you really want to store the strings try:
char ModuleList[10][80];
and
(void)strncpy(ModuleList[iLoop], strInput, 80-1);
ModuleList[iLoop][80] = NULL; // to guarentee NULL termination.
// in stead of ModuleList[iLoop] = strInput;
Hope that helps.
Jules
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Thanks for the help from you 3, helped a lot and I have it working now =)
- Travis
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I want to learn how to program a simple Databases.
What Database can i learn most from when am new??
I was thinking of making a simple text in a editbox and save it on a base,
where do i start??? Thank you 
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<<< In the name of GOD >>>
Hi.
I want to get string from Owner-Draw ListBox :
void CHlistbox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
CString string;
CDC *pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
CRect rc = lpDrawItemStruct->rcItem;
UINT action = lpDrawItemStruct->itemAction;
UINT state = lpDrawItemStruct->itemState;
UINT index = lpDrawItemStruct->itemID;
if(action & ODA_DRAWENTIRE)
{
GetText(index,string);
pDC->FillSolidRect(rc,RGB(0,0,0));
pDC->SetTextColor(RGB(100,100,50));
pDC->TextOut(rc.left+1, rc.top+1, string); // PROBLEM IS THERE
}
}
Adding string with ListBox :
void TestDlg::OnOK()
{
m_listbox.AddString("Hadi Rezaie");
}
My other problem is when i added 1 string, i cant adding other string with ListBox.
Please help me ...
Hadi Rezaie
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Is there a way to get a handle or a pointer to the scroll bar in a CListCtrl ?
Is there a way to disable and make the scroll bar in the CListCtrl class not appear?
Death reaches all
Your time will come billy boy
Eyal
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Hallo everybody! I'm developing an application with other people and we are using components.
I'm developing some components and I would like to know if someone know if it's possible (or how) to choose dynamically the ID for the new component at runtime.
Thanks
Bye bye
Nicola
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as far as i know the resource id's are a compile time thing that you would have a real hard time changing at run time ... its important to understand the difference between compile time and run time ... what you can and cant do
unless of course i dont understand what i'm talking about
always possible 
"every year we invent better idiot proof systems and every year they invent better idiots"
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You need to get with your fellow developers and standardize on a method to generate ID's. Basically, all you need to do is make sure that you don't duplicate the same number on the same dialog. One way to do this is allocate a range of ID's that you never use for static resources, and then create a function to allocate the ID's at runtime, which is simply a counter that returns a new number in the range everytime it's called.
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First, I think you read this writings.
I want to know how to get ip address and customer id(client id).
so, I want to put in data(CString variables) value made from above structure.
I don't know this at all.
Please reply this question quickly.
Please... Please...
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WSADATA wsaData;
struct sockaddr_in sock;
CString strHostname;
int lLen = 255;
WSAStartup(0x0101, &wsaData);
gethostname(strHostname.GetBuffer(lLen), lLen);
HOSTENT * lpHost = gethostbyname(strHostname.GetBuffer(lLen));
memcpy(&(sock.sin_addr), lpHost->h_addr_list[0], lpHost->h_length);
TRACE2 ("Host Name: %s IP address : %s\n",strHostname, inet_ntoa(sock.sin_addr));
WSACleanup();
Considderd to be the worlds fastest knoppenbonker.
10 Months of working experience with the worlds fastest copie paster(about 2000 lines a minute).
And experience with the one and only NewEra Guru.
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I'm using CDataSource, CSession etc to work with some database.
This database is having, for example, one table with two columns.
One is a self-incrementing counter (index) and other is a value.
My task is to write a function like this:
long Add(long val) {
return index_of_val_added;
}
I'm doing it this way:
long Add(long val) {
CCommand< CAccessor< table > > t;
t.Open(session, "insert into table(val) values(-1);", NULL, NULL, DBGUID_DEFAULT, FALSE);
t.Close();
t.Open(session, "select * from table where val=-1;");
int id = t.m_id;
t.Close();
CString s;
s.Format("update table set val=%d where id=%d", val, id);
t.Open(session, s, NULL, NULL, DBGUID_DEFAULT, FALSE);
t.Close();
return id;
}
I know, that it is ugly... Could anybody show me the correct way to do it?
With the best regards, Vitaly.
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I have a JPEG image to be printed onto the printer.How to this is possible in Windows NT
Raja sekhar
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