C / C++ / MFC

Re: Another threading question

25-Oct-04 10:36

While passing data between threads is certainly possible, it's not without risk. Read the following two articles on the subject:

http://flounder.com/workerthreads.htm
http://flounder.com/uithreads.htm

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

Blake Miller25-Oct-04 12:16

Blake Miller

25-Oct-04 12:16

PostThreadMessage will post a message into a thread's queue.
You can retrieve it with GetMessage or else wait for messages or other waitable objects to be signaled by using the function MsgWaitforMultipleObjects.

I would not read or write any data shared between one thread or another without guarding it with a critcal section, a mutex, or some other protection.

If you only need to modify a single long value, you can investigate InterlockedIncrement, etc.

Re: Another threading question

dharani26-Oct-04 21:37

dharani

26-Oct-04 21:37

If you want to pass the variable during startup of the thread itself - you can do as below..Assume var is the varible ( it can be a structure also ) you have to pass to the thread function ..

ULONG __stdcall ThreadFunc(LPVOID pParam); //declare thread function
CreateThread(NULL, 0, ThreadFunc,(LPVOID)var, 0, NULL);

Now "var" is passed to the ThreadFunc . Inside the ThreadFunc you can retrive the void param back to the original type as below

ULONG __stdcall ClientThread(LPVOID pParam)
{
int param=(int)pParam; (or) int param=(int*)pParam ; or replace int with your variable's type...

return 1;
}

and If you want to pass the param when the thread is running you can always use PostThreadMessage() with the same way of LOVOID(pParam) ...

Dharani Babu S

CharNext

Timothy Grabrian25-Oct-04 9:39

Timothy Grabrian

25-Oct-04 9:39

Can anyone help me convert this for loop:

PTCHAR Value = new TCHAR[2];
PTCHAR MRUList = new TCHAR[27];

//Get MRUList from the Registry
_tcscpy(MRUList,_T("abcdef\0"));//sample string

INT MRUListLength = _tcslen(MRUList);
//This is where I need the help
for(INT i = 0; i < MRUListLength; i++)
{
wsprintf(Value,_T("%c\0"),MRUList[i]);
//do something with Value now
}

//would delete the 2 PTCHARs but this is a sample

into something unicode compatible? I know I would need to use CharNext, I just can't figure out how.

Also I have heard of _TINT, Do I need to use that?

wWw.KruncherInc.cOm

Re: CharNext

David Crow25-Oct-04 10:47

25-Oct-04 10:47

KingKruncher wrote:
_tcscpy(MRUList,_T("abcdef\0"));//sample string

While it has nothing to do with Unicode, the extra '\0' is not necessary.

KingKruncher wrote:
I know I would need to use CharNext, I just can't figure out how.

How about:

for (LPSTR lpValue = MRUList; lpValue && *lpValue; lpValue = CharNext(lpValue))
{
    ...
}

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

Re: CharNext

Timothy Grabrian25-Oct-04 10:54

Timothy Grabrian

25-Oct-04 10:54

Thanks, it works. now what do I do with lpValue to get just that char, not the rest of the string?

wWw.KruncherInc.cOm

Re: CharNext

David Crow26-Oct-04 2:34

Finding COM Memory Leak in ISAPI Extension

26-Oct-04 2:34

How about *lpValue?

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

Turtle Hand25-Oct-04 9:36

Turtle Hand

25-Oct-04 9:36

I need some help finding a memory leak in an isapi extension I am maintaining. This extension leaks memory at a rate of 7mb every 5 minutes. I've been thru the Code Project article: Memory(-Leak) and Exception Trace (CRT and COM Leaks) by Jochen Kalmbach and it seems to be COM objects that are leaking. His approach doesn't work well with COM.

I've tried using UMDH.exe from MS, but am not able to set gflags for inetinfo.exe.

Any help at finding these leaks and/or using umdh.exe is appreciated.

<signature>
It's good to live,
Josef Wainz
Software Developer

Re: Finding COM Memory Leak in ISAPI Extension

Chris Richardson25-Oct-04 11:21

Chris Richardson

25-Oct-04 11:21

I can set the stack trace flag for inetinfo using gflags here (on a XP Pro SP2 box, running as admin). Is there an issue with permissions on your machine or is gflags just not working?

Chris Richardson

Displaying error message

SXP25-Oct-04 8:39

SXP

25-Oct-04 8:39

hello all..

i`m looking how to make when program display such message when it crashed

Assertion failed: f, file main.cpp, line 70

Abnormal program termination

sorry for my bad english, i`m from Estonia

BlackDice25-Oct-04 8:51

BlackDice

25-Oct-04 8:51

try using the following #defined constants

__FILE__
__LINE__
__FUNCTION__

Who are all these people and what are they doing in my house?...Me in 30 years, inside a grocery store

My articles[^]
bdiamond Sleepy | :zzz:

SXP25-Oct-04 8:57

SXP

25-Oct-04 8:57

and what actually must happend after i will define them...?!

will the program dispaly error messages as i want? Smile | :)

SXP25-Oct-04 9:10

SXP

25-Oct-04 9:10

ok ppl.. thx alot Wink | ;)

using assert() and __FILE__ / __LINE__ helped me Wink | ;)

thx

Left Button Drag-and-Drop

Blake Miller25-Oct-04 9:00

Blake Miller

25-Oct-04 9:00

__FUNCTION__ might not be available prior to Visual Studio 7.
I REALLY REALLY REALLY REALLY REALLY REALLY REALLY REALLY REALLY REALLY wanted something like this in Visual Studio 6.0 ... Cry | :((

Re: AfxMessageBox

Budric B.25-Oct-04 9:01

Budric B.

25-Oct-04 9:01

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_wcemfc4/html/aflrfafxmessagebox.asp[^]

Here's the reference. You can display the warning with ok etc.
you use the macros such as __LINE__ to tell the user which line the error occured as the previous poster suggested.

Erick 'El Matador' Demers25-Oct-04 7:18

Erick 'El Matador' Demers

25-Oct-04 7:18

Hi All, I try to convert files automatically when I drag-and-drop then onto a removable drive. I am able to do that using a ContextMenu with the right button drag-and-drop but how can I do that with the left button Drag-and-Drop ?

Thanks for your help.

Erick

time critical

LeeeNN25-Oct-04 6:55

LeeeNN

25-Oct-04 6:55

I have a task on PC, that must execute at about 100ms( 50~200ms is OK) interval to acquire data from outside target. Otherwise the data stream from outside target will be lost. I create a thread to do this. while (1) { DoTask(), Sleep(100) }. most of time it works fine, when PC is busy( e.g. open a doucumnet, or move mouse quickly ), the task won't run at 100ms interval. so I try to let the thread to be high priority. A little bit better, but still same. Is there any mechanism can guarantee this task run at about 100ms interval?

Thanks Confused | :confused:

David Crow25-Oct-04 7:12

25-Oct-04 7:12

Why aren't you using SetTimer(100)? Unless you are needing granularity less than 55ms, it should suffice. See this article for more.

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

Nemanja Trifunovic25-Oct-04 7:24

Nemanja Trifunovic

25-Oct-04 7:24

xianwuluo wrote:
Is there any mechanism can guarantee this task run at about 100ms interval?

There are no "guarantees", since Windows is not a RTOS. However, multimedia timers[^] can often be good enough. Just don't use "WM_TIMER" timers - they are easy to use, but with VERY low precision.

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

LeeeNN25-Oct-04 10:42

LeeeNN

25-Oct-04 10:42

Thanks for you replay.
WM_TIMER is same as Sleep(), if you set timer interval as 100ms. you are not guaranteed to run at 100ms even 200ms or 500ms.
For Multi-Media timer... I 'll try.

dharani26-Oct-04 21:42

dharani

26-Oct-04 21:42

You can use the following method...
Create a thread that will do your work every 100 ms..
ULONG __stdcall LogRotater(LPVOID pParam)// declare a thread function

And define it as below
ULONG __stdcall LogRotater(LPVOID pParam)
{
BOOL bStop=FALSE;
WriteMessage(msg,1);
while (bStop == FALSE)
{
HANDLE m_hEvent;
m_hEvent=CreateEvent(NULL,FALSE,FALSE,NULL);
switch (WaitForSingleObject(m_hEvent, DWORD(100)))
{
case WAIT_OBJECT_0:
bStop = TRUE;
break;

case WAIT_TIMEOUT:
//Do your work here ...

break;
}
}
return 0;
}

in case: WAIT_TIMEOUT you can do whatever you want to ...

Dharani Babu S

Find next file?

Larsson25-Oct-04 6:52

Larsson

25-Oct-04 6:52

Hello,
I working on FindNextFile(); and it works greate, but i is a problem.

I check for *.txt files in the c:\\ and when I find a file I take the file name and show it in my dialog window but the thing want stop, If there is only one file then I can check the file name so I don't use the same file, But if there is more than one file the funktion check and load the same files over and over.

Is there anyway to check so I don't use the same file over and over again?

Hmmm I use this function on a timer so it checks every second.

Please help me.

Re: Find next file?

David Crow25-Oct-04 7:19