I am setting a property, I need to know who is setting the property value? is this possible in haxe 3?
Also, can I know who is calling a function from inside the function itself?
Check out PosInfos. You use it like so:
public static function add(a:Int, b:Int, ?pos:PosInfos) {
trace( 'Called from ${pos.className}');
trace( 'Called from ${pos.methodName}');
trace( 'Called from ${pos.fileName}');
trace( 'Called from ${pos.lineNumber}');
return a+b;
}
add( 1, 1 ); // "pos" will automatically be filled in by compiler
Related
I now change my cuda program into an MFC project, I wrote the function of .cu as an interface function, So I can call it in MFC's dlg,Because I now use the UI thread call, I want to open a work thread to call, but failed.I am making AfxBeginThread, but it does not recognize my interface function.
I use vs2013, win7.
my interface function like this:
extern "C" float solveGPU(M_args Parameter_, double Mtime)
You could AfxBeginThread use but you have to call yout function from a new function or a static method with he following prototype:
UINT __cdecl MyControllingFunction( LPVOID pParam );
like this:
UINT __cdecl SolveGPUThreadFunction( LPVOID pParam )
{
YourDialogClass* pThis = (YourDialogClass*)(pParam);
pThis->result= solveGPU(pThis->Parameter_, pThis->Mtime);
}
and pass this pointer of your dialog as pParam of AfxBeginThread:
CWinThread* pCUDAThread = AfxBeginThread(&SolveGPUThreadFunction, this);
But you can think about using the std::thread instead.
A class t_analyser contains a function which performs some operations on a t_data object and outputs the results.
I would like to add to t_analyser a filter capability: a small and fast function
bool filter(const t_data & d) {...}
which allows to skip the analysis (and the output) if some conditions are met for that particular data. The filter should be setted up easily from the main, so I was thinking to store a shared function pointer in t_analyser and use a lambda to initialize it.
Is this a good approach? My concerns are related to the fact that many analysers can call the same filter function simultaneously in different threads, could this be a problem? Can I simply copy the pointer in the t_analyser's copy constructor? Any hint would be much appreciated.
This could be a problem if your filter function had side effects. Its signature is simple and says that it just makes some decision reading data from t_data, so make sure that t_data is not modified in parallel thread and you'll be fine.
Consider the following program:
#include <iostream>
struct X
{
void foo1(){ std::cout << "foo1" << std::endl; }
void foo2(){ std::cout << "foo2" << std::endl; }
};
typedef void (X::*MemberFunctionPointer)();
struct ByRef
{
ByRef( MemberFunctionPointer& f )
: f_( f )
{
}
void operator()()
{
X x;
(x.*f_)();
}
MemberFunctionPointer& f_;
};
struct ByValue
{
ByValue( MemberFunctionPointer f )
: f_( f )
{
}
void operator()()
{
X x;
(x.*f_)();
}
MemberFunctionPointer f_;
};
int main()
{
MemberFunctionPointer p = &X::foo1;
ByRef byRef( p );
ByValue byValue( p );
byRef();
byValue();
p = &X::foo2;
byRef();
byValue();
return 0;
}
Output:
foo1
foo1
foo2
foo1
Press <RETURN> to close this window...
From this you will notice that in the one case the member function pointer is passed by value (and not shared), and in the other it is passed by reference (and shared). When using the syntax:
foo( void( X::*f)() )...
the pointer to member function is passed by value, and is copied (and cannot be modified) again.
You can declare the function pointer as static + thread specific:
static _declspec(thread) FUNC_TYPE filterFunc;
Each thread that modifies filterFunc works on a different copy of the pointer.
I Read a few threads on how passing data from Workerthread to Main window(Dialog), but I still don't understand and still need help.
My workerthread should process some calculations and display the result during each loop to an edit on the GUI. I know, I should use PostMessage but since the calculation I'm doing implies a control element, I don't know how to solve this problem ...
//CWorkerThreadMgr.h manages the second thread
HRESULT Start (HWND hWnd);// from where the workerthread will be started
HWND m_hWnd ; //Window handle to the UI ;
HANDLE m_hTread; //handle of the worker thread
static UINT WINAPI ThreadProc( LPVOID lptest );
static UINT WINAPI ThreadProc( LPVOID lptest )
{
CWorkerThreadMgr* pCalculateMgr = reinterpret_cast< CWorkerThreadMgr*(lptest);
//The following operation:rand() *m_Slider.GetPos() should
//should be calculated and the result displayed each time in the edit box in the gui
for( UINT uCount = 0; uCount < 40; uCount++ ){
pCalculateMgr->rand() *m_Slider.GetPos();//?don't allowed to touch the gui!!
PostMessage(pCalculateMgr-> m_hWnd, WM_SENDCALCULATED_VALUE,wparam(rand() *m_Slider.GetPos(),0);
}
}
LRESULT CStartCalculationDlg::OnSendCalculatedValue( WPARAM Result, LPARAM )
{
// The resut should be displayed in the edit box
m_Calculation.Format(_T("%d"),???);
SetDlgItemText(IDC_CALCULATION, m_Calculation);
return 1;
}
void CStartCalculationDlg::OnHScroll(UINT nSBCode, UINT nPos,CScrollBar* pScrollBar)
{
m_SliderValue.Format(_T("%d"),m_Slider.GetPos());
SetDlgItemText(IDC_SLIDER_VALUE,m_SliderValue);
}
// Implementation in the CStartCalculationDlg.h
CWorkerThreadMgr m_WorkerThreadMgr //instance of the WorkerThreadMgr
CSliderCtrl m_Slider //member variable of the slider control
CString m_SliderValue // member variable of the edit box, where the current value of the
//slider will be displayed
CString m_Calculation // member variable of the edit box where the calculated
//result from the workerthread will be displayed via PostMessage
afx_msg LRESULT OnSendCalculatedValue( WPARAM, LPARAM );
afx_msg void OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar);
The next probem is that, when my slider control is moved and gets a new value, the thread procedure should know it and update the value of the slider. How can I manage to do it?
Instead of reading the slider position from the worker thread, read it in the UI thread and make it available to the worker thread.
I'm really no expert in this field, but I've done some worker threads as explained here.
What I would do in your case is create a static variable, like the "running" flag used in the article linked above, to hold the current position of the slider. Then, in the OnHScroll handler set it to the appropriate value.
As long as you only write to that variable from one thread, you should not have synchronization issues.
From worker thread:
m_data = foo();
PostMessage(hWndMain, UWM_SOME_CUSTOM_MESSAGE, 0, 0);
From UI thread:
LRESULT CMainFrame::OnSomeCustomMessage(WPARAM wParam, LPARAM lParam)
{
CMyData data = m_pWorker->GetData();
// Do stuff...
return 0;
}
GetData must be guarded by a critical section:
CMyData CMyWorker::GetData()
{
// This critical section is used in the worker thread too, whenever m_data is accessed.
m_lock.Lock();
CMyData data = m_data;
m_lock.Unlock();
return data;
}
See CCriticalSection on MSDN.
I have a class such as :
class MyStreamReader
{
public:
MyStreamReader(MyPramameter myPram) {.....}
~MyStreamReader() {}
DWORD WINAPI ReaderThread(LPVOID *lpdwThreadParam )
{
//....
}
};
and i want to call ReaderThread with WinAPI CreateThread. But CreateThread wants ReaderThread function wants a static function.
In some forms it is said that this is possible with boost library such as :
CreateThread(NULL, 0, boost::bind(&MyStreamReader::ReaderThread,this),
(void*)&myParameterObject), 0, NULL);
But i got compilation error:
'CreateThread' : cannot convert parameter x from 'boost::_bi::bind_t<R,F,L>'
to 'LPTHREAD_START_ROUTINE'
So as a result my questions:
Is it possible to call non-static function of a class from
CreateThread using boost lib(or any other method)
If not any C++ THREADing librray you may recomend(for visual C++) which i can call-run non static member function of a class as a thread?
Best Wishes
Update:
So first question: It seesm that it is impossible to call non-static c++ member function from CreateThread win API...
So any recomandations for C++ Multithreading lib whic is possible to call non-static functions as threads...
Update 2:
Well i try boost thread lib...seems it works...
MyStreamReader* streamReader = new MyStreamReader(myParameters);
boost::thread GetStreamsThread
( boost::bind( &MyStreamReader::ReaderThread, streamReader ) );
or (no need for bind)
boost::thread GetStreamsThread(&MyStreamReader::ReaderThread, streamReader);
AND in order to use boost::thread i update my class definition as:
class MyStreamReader
{
public:
MyStreamReader(MyPramameter myPram) {.....}
~MyStreamReader() {}
void ReaderThread()
{
//....
}
};
One common answer to this is to use a static "thunk":
class Worker
{
public :
static DWORD Thunk(void *pv)
{
Worker *pThis = static_cast<Worker*>(pv);
return pThis->DoWork();
}
DWORD DoWork() { ... }
};
...
int main()
{
Worker worker;
CreateThread(NULL, 0, &Worker::Thunk, &worker);
}
You can, of course, pack more parameters into your call to pv. Just have your thunk sort them out correctly.
To answer your question more directly, boost::bind doesn't work with the Winapi that way. I would advise using boost::thread instead, which does work with boost::bind (or, if you have a C++0x compiler, use std::thread with std::bind).
I have a class that contains a function that calls create thread, and needs to pass itself (this) as a parameter:
DWORD threadId;
HANDLE h = CreateThread( NULL, 0, runThread, this, 0, &threadId);
My runThread definition is as follows:
DWORD WINAPI runThread(LPVOID args)
{
Obj *t = (Obj*)args;
t->funct();
return 0;
}
Unfortunately, the object t that I get in runThread() gets garbage. My Obj class has a function pointer attribute. Could that be the problem?
class Obj{
void(*funct)();
and in the constructor:
Obj(void(*f)())
{
funct = f;
}
where is my mistake? The function pointer, the createThread itself, or type-casting? I tried whatever I could think of.
Assuming the object has been properly constructed, is there any chance that the object that is creating the thread has gone out of scope after CreateThread is called? This would leave your thread with a garbage object. If not, single step through the code with a debugger, and have a look at the objects 'this' pointer as the thread is being called, with a breakpoint at the thread start to see what it is getting as parameters.
The object was created in my main thread of execution. The error was because the object was going out of scope two lines down in that thread, so when the thread executed there was only garbage at the address.