Re: Do Not Understand why these three Files Will Not Compile

From:

Stuart Golodetz <blah@blah.com>

Newsgroups:

microsoft.public.vstudio.development,comp.os.ms-windows.programmer.win32,comp.lang.c++

Date:

Thu, 04 Nov 2010 23:37:18 +0000

Message-ID:

<iavg3b$muh$1@speranza.aioe.org>

On 04/11/2010 23:23, KevinSimonson wrote:

I've created the three files below and have gotten them into Visual
Studio 2010 (version 10.0.30319.1). I had a whole bunch of
compilation errors, but I've got them all fixed but two in "Bug.cpp".
I've embedded the error messages into the code with square brackets to
make it easier to see what the messages are referring to. What I'm
trying to do is get an example of a non-static function being called
every ten seconds. All this program does is write the contents of a
"Bug" object to a different file each time "problem()" is called.
This isn't the real software problem I'm working on; the one I'm
working on is much more complex. But the part I'm having trouble with
with the real software problem is this bit where a call to
"SetTimer()" needs to call a non-static method. Anybody have any idea
why this code won't compile for me?

Kevin S

---
BugMain.cpp------------------------------------------------------------------
// BugMain.cpp : Defines the entry point for the console application.
//

#include "Bug.h"
#include "stdafx.h"

int _tmain(int argc, _TCHAR* argv[])
{
   Bug bg = new Bug( 123, 456.789);
   bg.runIt();
   return 0;
}
---
Bug.h------------------------------------------------------------------------
#pragma once

class Bug
{
private:
      int abc;
   double def;

public:
   Bug ( int ab, double de);

   void runIt ();

   void problem ();

   static void* pObject;
};
---
Bug.cpp----------------------------------------------------------------------
#include "Bug.h"
#include<windows.h>
#include<stdio.h>
#include<fstream>
using namespace std;

char fileName[ 12];

Bug::Bug ( int ab
         , double de)
{
   abc = ab;
   def = de;
   strcpy( fileName, "Bug_000.Txt");
}

void CALLBACK repeatable ( HWND hwnt
                          , UINT uMsg
                          , UINT idEvent
                          , DWORD dwTime)
{
   Bug* bg = (Bug *) pObject; [Error: identifier "pObject" is
undefined]
   bg->problem();
}

void Bug::runIt ()
{
   pObject = this;
   SetTimer( NULL, 10000, repeatable); [Error: argument of type
"void (__stdc
} all *)(HWND hwnt, UINT uMsg,
UINT idEv
                                           ent, DWORD dwTime)" is
incompatible wi
void Bug::problem () th parameter of type "UINT"]
{
   ofstream outFile( fileName);
   outFile<< "abc == "<< abc<< " and def == "<< def<< "."<< endl;
   outFile.close();
   int dgt;
   for (dgt = 6; 3< dgt&& fileName[ dgt] == '9'; dgt--)
   { fileName[ dgt] = '0';
   }
   if (3< dgt)
   { fileName[ dgt]++;
   }
}

Well you're off-topic in comp.lang.c++, but judging by this:

http://msdn.microsoft.com/en-us/library/ms644906%28VS.85%29.aspx

It looks like you're passing three arguments to SetTimer when it expects
four. The result of that is that you're trying to pass uElapse (10000 in
your case) as nIDEvent, and lpTimerFunc (repeatable in your case) as
uElapse. Since repeatable is a callback function, not a UINT, you get
the error shown.

Suggested fix would be to pass in a suitable nIDEvent. Perhaps 0, since
you don't want to replace an existing timer, as in:

SetTimer(NULL, 0, 10000, repeatable);

Hope that fixes it -- it's a bit "off the top of my head", but in case
it helps.

---> And please don't post Windows-specific messages to comp.lang.c++
where they're not on-topic <---

Cheers,
Stu