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dear all,
i get a warning
D:\Schd\Config.cpp(117) : warning C4172: returning address of local variable or temporary
when i compile this code:-
char *CConfig::InputFilePath ()
{
char *inp;
** inp = new char[MAXCHARS];
int i= GetPrivateProfileString("Paths", "inputfile", "" ,inp, MAXCHARS, IniPath);
CString path(inp);
char filename[11];
int ch = 92;
unsigned int result;
char *pdest;
char iPath[MAXCHARS];
try
{
if ( (path == "") || CConfig::DoesDirectoryExist (inp) == false )
{
path = "";
strcpy(iPath,"");
return iPath;
}
pdest = strrchr( path, ch );
result = pdest - path + 1;
if ( result == strlen(path) )
{
strcpy(filename,"Input.con");
}
else
{
strcpy(filename,"\\Input.con");
}
strcpy(inp,path);
strcpy(inp, strncat( inp, filename,strlen(filename)));
}
catch(...)
{
path = "";
strcpy(iPath,"");
return iPath;
/*strcpy(filename,"\\Input.con");
strcpy(inp, strncat(_getcwd( buffer, _MAX_PATH), filename,strlen(filename)));*/
}
strcpy(iPath,inp);
delete [] inp;
return iPath;
}
also sometimes i get warning :-
detected memory leaks,
Object dump complete,
at location ** in the code
can anyone suggest some solutions! 
thanx,
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char *CConfig::InputFilePath ()
{
...
char iPath[MAXCHARS];
...
return iPath;
}The problem is very accurately described by the warning you're having. iPath gets destroyed as soon as InputFilePath exits, so returning its address is illegal. The simplest solution, probably, is to return a CString:
CString CConfig::InputFilePath ()
{
...
char iPath[MAXCHARS];
...
return iPath;
}Even if this fix works, I'd strongly suggest that you try to fully understand why your problem was happening, since it is a common error in beginners and something similar could shoot you in the future when least expected.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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thanx for the TIP Joaquín!
i'll keep it in mind and'll try to stick to it!
but is there anyother way to get rid if the specified scenario!
also can u help me with the memory leak while i'm deleting the pointer inp.
thanx a ton! ![Rose | [Rose]](https://codeproject.freetls.fastly.net/script/Forums/Images/rose.gif)
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also can u help me with the memory leak while i'm deleting the pointer inp.
** inp = new char[MAXCHARS]; should be
inp = new char[MAXCHARS]; I'm surprised that the code even compiled
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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sorry, but u misread my first thread.
** was to imply that THIS line of code gives memory leak warning! (** acted like a label in my thread, thats it!)
rishabhs
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dear all,
the code (in Bold) generates a memory leak and i get a warning, Object dump complete
char *CConfig::InputFilePath ()
{
char *inp;
inp = new char[MAXCHARS]; /*??Memory Leak, but it is deleted later in the code */
int i= GetPrivateProfileString("Paths", "inputfile", "" ,inp, MAXCHARS, IniPath);
CString path(inp);
char filename[11];
int ch = 92;
unsigned int result;
char *pdest;
char iPath[MAXCHARS];
try
{
if ( (path == "") || CConfig::DoesDirectoryExist (inp) == false )
{
path = "";
strcpy(iPath,"");
return iPath;
}
pdest = strrchr( path, ch );
result = pdest - path + 1;
if ( result == strlen(path) )
{
strcpy(filename,"Input.con");
}
else
{
strcpy(filename,"\\Input.con");
}
strcpy(inp,path);
strcpy(inp, strncat( inp, filename,strlen(filename)));
}
catch(...)
{
path = "";
strcpy(iPath,"");
return iPath;
}
strcpy(iPath,inp);
delete [] inp;
return iPath;
}
can someone tell me why this leak is occurring and how to prevent it!
thanx
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You need to look at the possibility of the function exiting before delete is called. From your code it looks like if an exception is thrown that's what happens; you catch it, and then return without freeing inp.
You may want to consider not allocating inp dynamically since it's always got a constant size (MAXCHARS).
char inp[MAXCHARS];
Another alternative is to dynamically allocate it, but on the stack using alloca:
char* inp = (char*)alloca(MAXCHARS);
Then you don't need to worry about explicitly freeing it since it will happen automatically.
Regards,
Alvaro
All you need in this life is ignorance and confidence, and then success is sure. -- Mark Twain
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You should look at your routine, and, before EVERY return, you should delete []inp.
You have 3 return points on your routine.
That's why some people advocate that routines should be structured so they have only one point of return. I'm not so rigid at this rule, but surely C++ beginners can benefit from writing routines with only one return point.
I see dumb people
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I agree. A single return is one of the rules I would stick to as a new programmer. After you have been programming for many years, you learn how to safely break the rules such as "single return" or "no goto".
Tim Smith
I'm going to patent thought. I have yet to see any prior art.
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I was drawn ploygon using Mouse on a DialogBox(not by Graphics commands of polygon), now i want to save this drawing to a file and restore it to back, how can i do this ?
Thank you
-Umakanth
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an example (but i can't remember its name) in msdn (first lesson about MFC) tells exactly what u need.
the example includes several steps, about using collections and how to save and open data.
includeh10
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if I Have DLL File And I want to use it in my project ...
How I Can Know How many function in this DLL File ,
what are They ? and What are the parameter for each Function in it and data type of them ?
Many Many Thanx for response
Hamoud Alhuttami
Yemen - Sana'a
![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
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open the dll as buffer, the info u need can be viewed from that buffer.
i don't know format of a dll file, but i did it before: as u want to know now.
note: the buffer is in a byte file (including zero in middle), but function's info is in asc ii format.
possile need no more than 1 day to go.
includeh10
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1st thank u very much
I wrote the following code to read dll :
(vb code )
dim b as byte
dim c as string*1
open "xx.dll" for random as #1 len=len(b)
open "xx.txt" for random as #2 len=len(c)
while not eof(1)
get #1,,b
c=chr(b)
put #2,,c
wend
close 1
close 2
then I opened xx.txt file to discovering this dll
i read name of functions but the file is not in text format there are symbols blanks ... try this code
it's no help me
suggest ...
hamoud
huttami@hotmail.com
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1st thank u very much
I wrote the following code to read dll :
(vb code )
dim b as byte
dim c as string*1
open "xx.dll" for random as #1 len=len(b)
open "xx.txt" for random as #2 len=len(c)
while not eof(1)
get #1,,b
c=chr(b)
put #2,,c
wend
close 1
close 2
then I opened xx.txt file to discovering this dll
i read name of functions but the file is not in text format there are symbols blanks ... try this code
it's no help me
suggest ...
hamoud
huttami@hotmail.com
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I have the following class
class DynamicArray {
private:
int* m_pInts;
public:
DynamicArray(int elements) {
m_pInts = new int[elements];
}
~DynamicArray() {
delete [] m_pInts;
}
};
This class creates an dynamically sized array of ints.
I also have the following function
DynamicArray GetDynamicArray() {
DynamicArray temp(89);
return temp;
}
unfourtunatly the destructor is called (on temp) when the function returns, which deletes my array of ints.
example:
int main() {
DynamicArray myArray = GetDynamicArray();
}
How do I make this work?
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Joshua Nussbaum wrote:
How do I make this work?
a) implement a copy ctor (the dtor will be still called for your local instance after it has been copied)
-or-
b) don't use local instance of your class, use a reference
void CreateMyDynamicArray(DynamicArray& ref) { ref.Create(89); }
Last line assumes you have an empty default ctor and a Create(int size) method.
PS: I suggest using a container (e.g. std::vector) instead of pointer/new/delete
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I agree with moak. Use std::vector and be done with it. To see the std::vector and dynamic data array in action, take a look @ my article and demo project, CDataFile[^].
- Nitron
"Those that say a task is impossible shouldn't interrupt the ones who are doing it." - Chinese Proverb
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Can u plz help me out in capturing a TCP packet(Using Winsock2). Plz provide me with the relevent sites/api names/specific functions to do the job.
Reply me soon
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For capturing the packet through Winsock2 look for the "raw sockets" (search for SOCK_RAW in MSDN). This feature is available in w2k and winXP only I guess.
The better way is to go through building the intermediate driver (NDIS), here you can intercept all packets (but the complexity is quite higher). And also you will not receive tcp traffic, but the raw ethernet frames - this gives you more power, but also more work.
Another approach is to use the Filter-Hook driver. This I don't know very well, but possibly it might be the way. For starter here, might be usefull http://www.codeproject.com/useritems/DrvFltIp.asp[^]
Hope this helps...
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If you are willing to settle for libpcap type of reading the wire you might want to consider looking at the winpcap libraries. You could in theory port routines from strong IDS systems (like Snort for example) with very little problem. You can check out winpcap over at http://winpcap.polito.it/[^] and use of the of examples to get the framework in place.
Once the framework is in place you can hook the filters to do your IDS bidding.
Good luck,
 SilverStr
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Hello,
This is a continuation of my earlier question. I've reposted because I have more information and my previous post was a bit misleading. I found that my application crashes during the "LoadFrame" statement below located in MyApp.cpp.
// create main MDI Frame window
CMainFrame* pMainFrame = new CMainFrame;
if (!pMainFrame->LoadFrame(IDR_MAINFRAME))
return FALSE;
m_pMainWnd = pMainFrame;
It seems that my DialogBar's controls are updating themselves before LoadFrame returns and the next statement executes (m_pMainWnd = pMainFrame). When these controls update, I'm trying to get information from the (MDI) Document to fill them, and the program crashes upon the execution of the following CDialogBar code (because m_pMainWnd is null at the time):
CGoalsDoc* pDoc = (CGoalsDoc*)((CMainFrame *)AfxGetApp()->m_pMainWnd)->GetActiveFrame()->GetActiveDocument();
Why are my controls trying to update (e.g., OnKillFocusEditBox1) before the main frame has been created and "m_pMainWnd" has a value? Is there an easy way around this? I don't think I monkeyed with the MFC Wizard too much, but I may have changed something small, yet important.
Thanks!
JennyP
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Does
m_pMainWnd = new CMainFrame();
if ( !static_cast < CMainFrame* > (m_pMainWnd)->LoadFrame(IDR_MAINFRAME) )
{
return FALSE;
}work?
This way you have a non-NULL m_pMainWnd before LoadFrame() executes.
Alternatively, you can wrap your GetActiveDocument call in a
if (initialised)
clause and set a bool initialised to true after you have loaded the MainFrame.
"My opinions may have changed, but not the fact that I am right."
Found in the sig of Herbert Kaminski
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After some more time, I found the issue (loosely related):
After deleting a control from my dialog, VC++ assigned the first tab stop to a edit control. I handle the kill-focus message for this edit box and this handler crashes the program because it tries to access the document directly.
Therefore, the fix was to change my tab order so that THIS control was not the first.
Good lesson, but it took too much time to debug for me.  
JennyP
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