Re: How to Declare Pointer to Member Function?

From:
"Doug Harrison [MVP]" <dsh@mvps.org>
Newsgroups:
microsoft.public.vc.mfc
Date:
Mon, 16 Jul 2007 13:50:45 -0500
Message-ID:
<54fn9314ha02cfh0sfq9t63drf5hgbdvov@4ax.com>
On Mon, 16 Jul 2007 13:39:06 -0500, "jp2code" <poojo.com/mail> wrote:

I have a thread that needs to make data visible to a function inside a
separate class.

In the past, I was using PostMessage to get my information to the class
function, but occasionally a message gets lost this way.


It shouldn't.

I could declare the class function as static, but then the function would
not be able to interact with other parts of the class.

The data is thread safe.

// header:
typedef void (*PtrToLpMsg)(LPTSTR lpMsg);
PtrToLpMsg g_AddStatusMsgFn;

// code:
CMain::CMain()
{
 g_AddStatusMsgFn = AddStatusMsgA;
}

void CMain::AddStatusMsgA(LPTSTR lpMsg)
{
 // other code
}


This is how you do it. Note that to call a non-static member function
through a pointer to member function, you need a pointer or reference to an
object of the class to which the member belongs.

class CMain
{
public:

   CMain();

   void AddStatusMsgA(LPTSTR lpMsg)
   {
   }
};

typedef void (CMain::*PtrToLpMsg)(LPTSTR lpMsg);
PtrToLpMsg g_AddStatusMsgFn;

CMain::CMain()
{
   g_AddStatusMsgFn = &CMain::AddStatusMsgA;
}

void f(CMain* p)
{
   (p->*g_AddStatusMsgFn)(0);
}

The usual caveats about global data apply.

--
Doug Harrison
Visual C++ MVP

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