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You are using either a class or a template that is called "GUIQueue".
Never mix C++ objects with malloc/free. Use new/delete instead.
Why? Because the object's constructor and destructor won't get called when you are using malloc and free.
What kind of errors you get depend on the C++ object you are using.
--
Roger
It's supposed to be hard, otherwise anybody could do it!
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I tried switching to delete and new, but down the line of delete it still runs into the same method that free does, and cause the same error. Upon review of the last method, in the method header info, it says that it checks to see if the pointer is in the local heap, which i dont think it is in the local heap, cause its a different thread thats creating it, so this could be the main problem.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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I'm not really familiar with multithreaded application, but I think you will need to block the
access to your data when you free it; it looks like one of your thread will try to access the data while your are free-ing it.
have a look at mutex, critical section, and all the other related mechanism for locking access to your data to only one thread.
Maximilien Lincourt
Your Head A Splode - Strong Bad
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I think I see what your saying, but the only thing that accesses the data after its created, is the same thread that free()'s it. So its not something else trying to access the data. Is that what you were getting at?
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Jader89 wrote: newMsg->data = (char*)malloc( sizeof(msg.u.reqvid) );
Note the value of newMsg->data after this point.
Jader89 wrote: free(newMsg->data);
Note the value of newMsg->data before this point. Is it the same as it was after the call to malloc()? If not, that's why free() is failing.
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The pointer is a valid one, and the same as it is when its created.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Can you confirm that this works:
class GUIQueue
{
public:
char *data;
};
void main( void )
{
GUIQueue *newMsg = (GUIQueue *) malloc(sizeof(GUIQueue));
newMsg->data = (char *) malloc(15 * sizeof(char));
if (newMsg->data != NULL)
{
free(newMsg->data);
newMsg->data = NULL;
}
if (newMsg != NULL)
{
free(newMsg);
newMsg = NULL;
}
}
"Take only what you need and leave the land as you found it." - Native American Proverb
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I'll try this out. As a side note, the free(newMsg) works fine... Its just the char* thats in the struct GUIQueue that doesnt seem to want to free... Ill reply soon on the results.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Yup, this segment of code works fine...
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Then some other piece of code is changing newMsg->data before free() is called. Either take away from your current program, or add to this temporary program, until you find the offending statement(s).
"Take only what you need and leave the land as you found it." - Native American Proverb
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Well it seems the mix up occurs somewhere between pushing the it on the queue, and taking it off. I tried just a push followed by a pop, and i run into the problem. Any ideas why?
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Jader89 wrote: Any ideas why?
Not without seeing the code for the 'push' and 'pop' operations.
"Take only what you need and leave the land as you found it." - Native American Proverb
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The queue:
std::queue<GUIQueue*> GUIQ;
the struct:
struct GUIQueue<br />
{<br />
bool isBmp;<br />
int size;<br />
char* data;<br />
};
other than that, i just imported the queue.h header file,
and used the methods push(), and front(), since pop doesnt really do anything
other than completely remove the front of the queue.
here is the failing code as one thread, also note, that without the push, and pop, the free()'s worked fine.:
GUIQueue* newMsg = (GUIQueue*)malloc( sizeof(GUIQueue) );<br />
memset( newMsg, 0, sizeof(GUIQueue) );<br />
newMsg->data = (char*)malloc( sizeof(msg.u.reqvid) );<br />
memcpy( newMsg->data, &msg, sizeof(msg.u.reqvid) + sizeof( MsgHeader ) );<br />
newMsg->size = sizeof(msg.u.reqvid) + sizeof(MsgHeader);<br />
newMsg->isBmp = true;<br />
GUIQ.push( newMsg );<br />
<br />
GUIQueue* test = (GUIQueue*)GUIQ.front();<br />
GUIQ.pop();<br />
if( test->data != NULL )<br />
{<br />
free(test->data);<br />
test->data = NULL;<br />
}<br />
if( test != NULL )<br />
{<br />
free(test);<br />
test = NULL;<br />
}
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Correction:
If i keep the same pointer name, newMsg, and call free on that, it will work for both ->data, and on itself. But if i switch pointers names ,( i.e. GUIQueue* test = newMsg ), then call do the same free()'s but on test, it fails.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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I figured out the problem, if you look back in my code, i malloc a certain amount, then do a memcpy that is bigger than that amount, causing it to do something bad... 8), easy error for alot work, lol.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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DavidCrow wrote: newMsg->data = (char*)malloc( sizeof(msg.u.reqvid) );
should that be something like :
newMsg->data = (char*)malloc( msg.u.reqvid * sizeof(char ) );
Maximilien Lincourt
Your Head A Splode - Strong Bad
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Its a typedef struct, im pretty sure this works, cuase it works in other parts of my code.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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I think this might be a hack, but im gonna create another GUIQ, with ready to be freed pointers, and when there used in my other thread, they get thrown away in this queue, which the other thread checks, and if there is anything in there, its free's it. Seems like a lot of work to free memory. Wonder why you it must be local heap to be able to free it.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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Didnt work, same problem.... Boo.
"There are 10 types of people, those who understand binary, and those who don't."
- Somebody, not me.
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I want a different behaviour for a button when keeping it pressed with the LButton of the mouse.
To repeat the BN_CLICKED using a timer inside the new class is no big deal, it all works fine and dandy.
The thing is that I want to add a new notification code to be repeated while the button is pushed in, something like BN_KEPTDOWN, but I'd like to pick a value that doesn't conflict with some other notification code in a later release of DevStudio and/or MFC (running on VC6 at the moment).
Are there some guidelines regarding creating new notification codes?
I tried MSDN but I was unable to find anything about this.
Links, anyone?
--
Roger
It's supposed to be hard, otherwise anybody could do it!
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you can use WM_USER then just add to it if you need more than one
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Probably, but WM_USER has nothing to do with notification codes since WM_USER is a message ID.
When you handle the BN_CLICKED event, a WM_COMMAND message is sent from the child to the parent with a 16-bit notification code in the WPARAM parameter of the message. The other 16 bits are the ID of the control and the LPARAM parameter is the window handle of the control.
This is normally taken care of by the framework/MFC.
What I want is a new notification code that is guaranteed not to conflict with other notification codes for buttons.
--
Roger
It's supposed to be hard, otherwise anybody could do it!
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how to obtain file permision (such as drwx---r-x) from web host by ftp connection?
any samples, comments or links?
thanks
includeh10
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How about CFtpFileFind::IsReadOnly(), CFtpFileFind::IsDirectory(), CFtpFileFind::IsSystem(), CFtpFileFind::IsHidden(), and CFtpFileFind::IsArchived()?
"Take only what you need and leave the land as you found it." - Native American Proverb
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no.
unix permission has 10 digits:
prwxrwxrwx
includeh10
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