C / C++ / MFC

User 5838528-Nov-06 14:30

User 583852

8-Nov-06 14:30

There must be a reference to it somewhere. Use windows explorer search or VS Find in Files feature to look for any file in your project that contains the text "sensors". If using Find In Files make sure you set the file type to *.*

Christian Graus8-Nov-06 15:31

Christian Graus

8-Nov-06 15:31

Yeah, that's what I was advocating.

Christian Graus8-Nov-06 15:30

Christian Graus

8-Nov-06 15:30

There has to be a reason that it's expecting to find this file, you searched for the word 'sensors' in the text of your entire project ?

David Crow9-Nov-06 3:52

David Crow

9-Nov-06 3:52

Did you look in the project's .dsp file?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

How to call a function inside a thread

celllllllll9-Nov-06 7:25

celllllllll

9-Nov-06 7:25

no, will try that..

Thanks

C++Prog

Llasus8-Nov-06 12:06

8-Nov-06 12:06

Does anyone know how i can call a function I created inside a thread? Thanks a lot!

I have a class with a list object in it. I need to do some processing that's why
I created a thread which does that. I have created another function which accepts
3 or 4 strings inside the class...
void AddListItem(CString strbufffn, CString strbuffip, CString strbuffdate, CString strbuffstat);
note that inside the function im adding items to the CListCtrl of my List object

and i need the information processed by my thread to be passed to the function.
DWORD WINAPI ReceiveThread(LPVOID lParam)
{
//some processing here
//need to call the AddListItem here
}

Again thanks for the help!

Stephen Hewitt8-Nov-06 12:32

8-Nov-06 12:32

In general you just call it. Be warned however; multithreading introduces many new and often unexpected complexities to an application. If you don't understand these complexities you're better off avoiding it. For example something as simple as incrementing a variable might not work as expected if more then one thread tries to "touch" it at the same time. If you've never heard of EnterCriticalSection, LeaveCriticalSection, InterlockedIncrement and many others, don't even consider using multiple threads.

Steve

Llasus8-Nov-06 12:41

8-Nov-06 12:41

Thanks but I already tried that and unfortunately it did not work. It had an error saying that the function is an external function or something.

Stephen Hewitt8-Nov-06 12:44

8-Nov-06 12:44

This doesn't sound like a threading problem to me. Can you call the function at all even when no threading is used (in the same file as you do when threading is used)?

Steve

Llasus8-Nov-06 13:00

8-Nov-06 13:00

yes I can. I've been looking at every possible problem but it seems like the thread is it. the thread can't see the function i declared in the main class.

Stephen Hewitt8-Nov-06 13:05

8-Nov-06 13:05

Llasus wrote:
the thread can't see the function i declared in the main class.

The compiler knows nothing about threads. Threads are supported by the OS and the C-runtime library so the visibility of functions will not be effected. That's why I suggested putting the call to the function in the same file (and as close as possible) as the call made in the thread function: as location is an issue.

Steve

Llasus8-Nov-06 13:13

8-Nov-06 13:13

I tried putting the function in the same file as the thread and it still generated the same error as it cant see the function when called in the thread.

Stephen Hewitt8-Nov-06 13:15

8-Nov-06 13:15

Perhaps if you posted some code and the exact error message text something might reveal itself.

Steve

Llasus8-Nov-06 13:27

8-Nov-06 13:27

Ok here are cutout of the codes that i have..

in LPAServerDlg.h

class CLPAServerDlg : public CDialog<br />
{<br />
// 構築<br />
public:<br />
        //some declaration here<br />
	void AddListItem(CString strbufffn, CString strbuffip,<br />
		CString strbuffdate, CString strbuffstat);<br />
        //some declaration here<br />
}

in LPAServerDlg.cpp

//headers and definitions<br />
DWORD WINAPI ListenThread(LPVOID lParam);<br />
DWORD WINAPI ReceiveThread(LPVOID lParam); //heres the thread<br />
<br />
class CAboutDlg : public CDialog<br />
{<br />
//codes here<br />
};<br />
<br />
CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)<br />
{<br />
//codes here<br />
}<br />
//more codes here<br />
<br />
DWORD WINAPI ReceiveThread(LPVOID lParam)<br />
{<br />
...codes<br />
AddListItem(strbufffn, strbuffipa, "Time", "Printing");<br />
...codes<br />
}<br />
<br />
DWORD WINAPI ListenThread(LPVOID lParam)<br />
{<br />
..codes<br />
hThread = CreateThread(0, 0, ReceiveThread, (LPVOID)Message, 0, NULL);<br />
..codes<br />
}<br />
<br />
void CLPAServerDlg::AddListItem(CString strbufffn, CString strbuffip,<br />
		CString strbuffdate, CString strbuffstat)<br />
{<br />
	int nItem;<br />
<br />
	nItem = m_ListFile.InsertItem(0,strbufffn);<br />
	m_ListFile.SetItemText(nItem, 1,strbuffip);<br />
	m_ListFile.SetItemText(nItem, 2,strbuffdate);<br />
	m_ListFile.SetItemText(nItem, 3,strbuffstat);<br />
}<br />

error C2440: '=' : from 'void (__thiscall CLPAServerDlg::*)(class CString,class CString,class CString,class CString)' to 'void (__cdecl *)(class CString,class CString
,class CString,class CString)' cannot change. (see the new of operation ; help)

sorry bout the error message.. its all in japanese and i just translated it. Thanks again for all your time and help!

Stephen Hewitt8-Nov-06 14:01

8-Nov-06 14:01

Can you indicate on which line the error occurs?

Steve

Llasus8-Nov-06 14:09

8-Nov-06 14:09

oh, sorry but i pasted the wrong error message. the error line there occured on the call of the AddLIstItem() on the ReceiveThread.

Stephen Hewitt8-Nov-06 14:12

8-Nov-06 14:12

I'm still not sure where the error occured or now if the error you gave is the correct error. If the error message is correct it means you're trying to assign a member function pointer to a pointer that expects a "free" (non member) function.

Steve

Llasus8-Nov-06 14:25

8-Nov-06 14:25

I made changes in my code earlier thats why i pasted the wrong error message. I attempted earlier to pass the function's address to the thread but failed. Still i cant directly call a function of the class inside a thread even though they are of the same file.
Here is the correct error message..
E:\Program Files\Microsoft Visual Studio\MyProjects\LPAServer\LPAServerDlg.cpp(355) : error C2065: 'AddListItem' : It is the discernment child who is not defined.
Again, thanks alot for the time Steve

Stephen Hewitt8-Nov-06 14:28

8-Nov-06 14:28

I haven't got the whole file so line numbers don't tell me where the error occured. You'll have to show post some code and mark the line where the error occurs.

Steve

Llasus8-Nov-06 14:32

8-Nov-06 14:32

DWORD WINAPI ReceiveThread(LPVOID lParam)<br />
{<br />
...codes<br />
AddListItem(strbufffn, strbuffipa, "Time", "Printing"); //error occurs here<br />
...codes<br />
}

Stephen Hewitt8-Nov-06 14:48

8-Nov-06 14:48

ReceiveThread is a global function not a class member. AddListItem is a member function. You have to call a member function either in another member function or qualify the call using a . or a ->.

Steve

Mark Salsbery8-Nov-06 13:26

Mark Salsbery

8-Nov-06 13:26

You need an object of your class type to call a non-static member function of that type.
You could pass an object (pointer) into your thread proc via the lParam:

DWORD WINAPI ReceiveThread(LPVOID lParam)
{
MyClass *pMyClass = (MyClass *)lParam;
//some processing here
pMyClass->AddListItem(...);
}

Pass the MyClass pointer as the LPVOID lpParameter in the CreateThread() call.

Llasus8-Nov-06 13:37

8-Nov-06 13:37

ok ill try that in a bit. but would it also be possible of passing the pointer of the function?