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Do you know why the access violation is occurring? If not, what do you hope to achieve be catching it?
Steve
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I am using three layer allocation of arrays of memory.
i want to free this memory and again i want to reallocate the memory
dynamically
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Can you show some code and explain the fault more clearly.
Steve
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My structure is like this:
-----------------------------
typedef struct
{
HTREEITEM* pParam;
int nCnt;
} MILPARAMETER;
typedef struct
{
MILPARAMETER* pMilParam;
HTREEITEM* pMessage;
int m_nMsgIndex;
int nCnt;
} MILMESSAGE;
typedef struct
{
MILMESSAGE* pAvionicsMsg;
MILMESSAGE* pMissionMsg;
HTREEITEM* pAvionicsTree;
HTREEITEM* pMissionTree;
CString *pStrAvionicsBus;
CString *pStrMissionBus;
int m_nAvoinicsCnt;
int m_nMissionCnt;
} MILLRUNAMES;
Now I want to dynamically allocate and deallocate the memory
for the pointer variables.
Allocation there is no problem for deallocation is the only problem.
How to deallocate this memory?
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When posting code, please use the 'code' tag to format it properly.
Anyway, you still didn't post the real useful code: the part where you allocate and deallocate the memory. Without that, it will be very difficult to help you. I also fully agree with the other posters: it seems you don't really understand how to allocate and deallocate the memory properly and catching an exception in those circumstances without fixing the actual problem would be really crazy.
Furthermore, are you sure you want to use arrays of CString ? Do you want to store multiple strings ?
I also encourage you to take a look at std::vector or std::list, because it seems you want to work with arrays of varying size, in which case such a container would make things way more simple.
Additionally, I also encourage you to focus a bit more on encapsulation: as you are using C++, I would provide a constructor and destructor for your structures, which will be responsible to allocate and deallocate the memory properly. Also, the members would be private so that only the structure can allocate memory for the varialbes. This will make your code much more simple and less error prone.
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Hi,
I have 3 and 4 layer of tree structures of variable sizes.
If you click on one node that type of record details should come from database. and that record will be filled in the controls of the dialog.
These layers are dynamic and the structure details i have already posted.
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Did you actually have a look at the suggestions that were given to you or you just expect that somebody provides the solution on a silver plate to you ?
Did you look at the std::vector documentation ? What's the problem with using a vector ? Did you rewrite your code properly so that your allocations and deallocations are hidden in a class so that it is not spread across the whole program (aka encapsulate your data properly). As long as you don't show us precisely how the memory is allocated and deallocated, we won't be able to help. I suppose you didn't do it because it is too complicated because everything is spread across your code. One additional reason to try to encapsulate your data.
If you want help from us, you will need to read and try to understand what people are telling you, not expect a complete solution.
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Sakhalean wrote: Now I want to dynamically allocate and deallocate the memory
for the pointer variables.
MILLRUNAMES.pAvionicsMsg = new MILMESSAGE; Sakhalean wrote: How to deallocate this memory?
delete MILLRUNAMES.pAvionicsMsg;
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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Or, to be complete:
MILLRUNAMES.pAvionicsMsg = new MILMESSAGE[3];
delete[] MILLRUNAMES.pAvionicsMsg;
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You haven't indicated where the problem is occurring. I'll help if I can, but I'm not going to do it for you.
Steve
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Sounds like you've got a bug in your code. Concentrate on finding that rather than trying to paper over the cracks by catching an exception that may or may not exist.
Here's another thought - if you're playing with dynamically allocated arrays why aren't you using std::vector?
Cheers,
Ash
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I have a DWORD and i want to convert it into a time format.
Eg. DWORD is = 41107ECE
I want it should be in format as = 2004/08/04 Wed 06:14:38 UTC
How can I do this conversion?
Plz help me.
Regards
Nikesh
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Clearly that depends on the encoding of the date in the DWORD, which you haven't mentioned.
Steve
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Nikesh Jagtap wrote: I have a DWORD and i want to convert it into a time format.
Assuming that you mean your DWORD is actually a time_t value then you can use one of the Time Management Routines[^].
It's time for a new signature.
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This way:
char buf[0x20];
DWORD dw = 0x41107ECE;
time_t t = dw;
struct tm * ptime;
ptime=gmtime(&t);
strftime(buf,0x20,"%Y/%m/%d %a %H:%M:%S UTC\n",ptime);
printf(buf);
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Hi,
CString sz;
sz.LoadString( HINSATANCE hin,UINT id);
How to achieve the above thing by using std::string instead of cstring???
Thanx.
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There's no such functionality in STL for std::string, but course if you could convert CString to std::string.If you are asking how to read string from a file look up ifstream class.
Life is a stage and we are all actors!
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You have to do it yourself. LoadString[^] is a windows specific function (wrapped by CString) and std::string is standard C++ and thus can't be expected to have any OS specific functions.
Steve
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Hi,
First you need to call FindResource[^] to find the resource string then you can call SizeofResource[^] to get the size of the string so you can resize your std::string and finally call LoadString[^] to copy it.
Best Wishes,
-David Delaune
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Hi,
Not sure who gave me a one vote... but the solution I presented is a secure and safe method for loading a std::string from a resource.
The method presented by Aescleal will fail for a string greater than the 4096 constant. The wstring solution presented by Stephen Hewitt just flat out doesn't work for std::string
Best Wishes,
-David Delaune
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It does for a wstring (which was all it was intended to, it wasn't a reply to the OP but to Aescleal).
It's documented. MSDN (on LoadString):
nBufferMax [in]
int
The size of the buffer, in characters. The string is truncated and null-terminated if it is longer than the number of characters specified. If this parameter is 0, then lpBuffer receives a read-only pointer to the resource itself.
Secondly, I tried it (after reading the documentation thoroughly first) and verified that it did work.
Finally, your technique will not work. LoadResource returns nothing that LoadString can consume.
Steve
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Stephen Hewitt wrote: Finally, your technique will not work. LoadResource returns nothing that LoadString can consume.
Hi Stephen,
You may be correct. I was thinking that you could just do something like this:
HRSRC hres = FindResource(NULL, MAKEINTRESOURCE(IDS_SOMESTRING), RT_STRING);
DWORD dwSizeRes = SizeofResource(NULL,hres);
char *p = NULL;
int result = LoadString((HINSTANCE)&__ImageBase,AFX_IDS_APP_TITLE,p,0);
std::string s(p,dwSizeRes);
Which is not much different than what you posted.
With the method that you posted...I am thinking that the std::string would need a NULL terminator in the string resource. I admit that I have not tried either method (including the one I just typed above). I will test both methods later when I get some free time.
Best Wishes,
-David Delaune
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Hey Steve
I just spent 30 minutes testing both of our code samples. I could not get the code you wrote working for std::string probably because the resource strings are actually stored in Unicode within the PE files. However for wstrings your code is absolutely perfect. I suspect... that the brilliant code you posted could be actually be modified to utilize wcstombs and work for both ANSI and Unicode builds.
As for my code sample... I had even less success although I was eventually able to get it working. I had to re-read some of the MSDN docs and ended up using FindResourceEx with the language identifier. To make things worse the address I was recieving was the start of the string resource block. I had to load the string block into an HGLOBAL and walk the string table before I could even read the string. 
Anyway I just wanted to let you know that you were correct.
Best Wishes,
-David Delaune
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I didn't give you a 1 vote but the method I outlined will work for strings greater than 4096 characters, it just won't load the whole string. If you're really worried about that you have to use the OS/2 vintage "try it once to fail, once to succeed" method of sizing buffers.
And it'd be fairly easy to change Stephen's method to work for std::string - depending on how much you know about the resource and the characters in it it's either trivial (use the two iterator string constructor) or slightly harder (use wcstombs).
Ash
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