C / C++ / MFC Discussion Boards

Gary Kirkham14-Apr-03 5:58

14-Apr-03 5:58

I agree, However in the deep dark recesses of the peanut I call a brain I seem to remember you could access the other class by offsetting the class A pointer by some amount. The classes are stored contigously in memory. I just can't remember the details.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Re: Multiple inheritance

Maximilien14-Apr-03 6:03

Maximilien

14-Apr-03 6:03

But That's an ugly hack!

Max.

Maximilien Lincourt
For success one must aquire one's self

Re: Multiple inheritance

Gary Kirkham14-Apr-03 7:26

Gary Kirkham

14-Apr-03 7:26

Agreed

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Re: Multiple inheritance

Tim Smith14-Apr-03 6:08

Tim Smith

14-Apr-03 6:08

B *b = static_cast <B *> (static_cast <C *> (this));

This assumes this is a pointer to A.

You do have to remember that in theory, this is very unsafe since it assumes that the member function is in fact being invoked from an instance of C. However, as long as that is the case, it works perfectly well.

Tim Smith

I'm going to patent thought. I have yet to see any prior art.

Re: Multiple inheritance

Maximilien14-Apr-03 6:28

Maximilien

14-Apr-03 6:28

B *b = static_cast < B *> (static_cast< C *> (this));

That's a heck of a line of C++ ! Big Grin | :-D

Max.

Maximilien Lincourt
For success one must aquire one's self

Re: Multiple inheritance

Gary Kirkham14-Apr-03 7:43

Gary Kirkham

14-Apr-03 7:43

Unfortunately, A doesn't know who C is...C could be any one of a number of classes.

Gary Kirkham

A working Program is one that has only unobserved bugs

I thought I wanted a career, turns out I just wanted paychecks

Re: Multiple inheritance

Tim Smith14-Apr-03 9:51

Tim Smith

14-Apr-03 9:51

Oh well, that depends on C being well known. :/

Tim Smith

I'm going to patent thought. I have yet to see any prior art.

Re: Multiple inheritance

#realJSOP14-Apr-03 6:42

#realJSOP

14-Apr-03 6:42

why don't you do this:

class A {};
class B: public A {};
class C: public B {};

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CreateProcess ???

will138314-Apr-03 5:38

will1383

14-Apr-03 5:38

I'm using the CreateProcess to run an application. Here's how I am calling it:

if (CreateProcess(cmd, cmdline,
NULL,
NULL,
TRUE,
0 /*CREATE_NEW_CONSOLE */,
NULL,
NULL,
&si,
&pi) != 0){

My problem is I'm passing in a command line option, but the option is NOT being sent to the application being run. The app runs and Create Process returns correctly, but the app I'm running just doesn't do what I want it to.

I've looked through the MSDN definition, but I haven't found a solution. I've tried everything it suggests, but it still doesn't work, not matter what command line option I put in there. None of them get passed in.

Anyone have any ideas or suggestions? Thanks!

Re: CreateProcess ???

Rage14-Apr-03 6:08

Rage

14-Apr-03 6:08

merge the app string and the commandline string into one, put it instead of your command, set the commandline to NULL.

~RaGE();

Re: CreateProcess ???

will138314-Apr-03 6:27

will1383

14-Apr-03 6:27

I've already tried that as well. I've tried all the ways that MSDN suggest. When I use that method, I get an error 2, which means "The system cannot find the file specified." or ERROR_FILE_NOT_FOUND. But the file is there, and the path is correct.

I also tried adding the app name to the commandline string and setting the command to NULL, as well as having the command in there as well.

Any other ideas or suggestions?

Re: CreateProcess ???

Rage14-Apr-03 6:43

Rage

14-Apr-03 6:43

Are you _really_ sure no command line is passed ? Already tried to start some dummy batch file with a echo %1 or something like that, that would display the command line ?

~RaGE();

Re: CreateProcess ???

Rage14-Apr-03 6:45

Rage

14-Apr-03 6:45

If you really don't get it to work, but need it to continue coding, use a ShellExecute or WinExec until you have figured it out. Roll eyes | :rolleyes:

~RaGE();

Re: CreateProcess ???

valikac14-Apr-03 7:41

valikac

14-Apr-03 7:41

Pass NULL for the first parameter inplace of "cmd." Post an example of the command line you pass in as the second parameter "cmdline."

Kuphryn

I can´t understand why it doesn´t work

Martin_Viet14-Apr-03 5:24

Martin_Viet

14-Apr-03 5:24

hi.

I´m making a easy network application. So I did a new class which inherits from CSocket. Then I overwrite OnConnect and OnReceive, where I´ve written :

<br />
void SurSocket2::OnConnect(int nErrorCode) <br />
{<br />
	// TODO: Add your specialized code here and/or call the base class<br />
	SurSocket2 s;<br />
<br />
	Accept(s);<br />
	<br />
	CSocket::OnConnect(nErrorCode);<br />
}

void SurSocket2::OnReceive(int nErrorCode) <br />
{<br />
	// TODO: Add your specialized code here and/or call the base class<br />
<br />
   TCHAR buff[4096];<br />
   int nRead;<br />
   nRead = Receive(buff, 4096);<br />
   <br />
   AfxMessageBox(buff);<br />
   <br />
	<br />
	CSocket::OnReceive(nErrorCode);<br />
}

.... Finally, in the main dialog i have:

	int nPort = 21010;<br />
<br />
    socket.Create( nPort);<br />
<br />
	socket.Listen(50);

Why it doesn´t work? Confused | :confused:

el hombre arriesga su vida cada vez que elige y eso es lo que lo hace libre

Re: I can´t understand why it doesn´t work

Joaquín M López Muñoz14-Apr-03 5:30

Joaquín M López Muñoz

14-Apr-03 5:30

SurSocket2 s;

Accept(s);

After accepting the incoming connection for s, this variable goes out of scope and consequently its destructor gets called. The observable result from the other side of the connection is immediate termination of the connection.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: I can´t understand why it doesn´t work

Martin_Viet14-Apr-03 5:46

Martin_Viet

14-Apr-03 5:46

Well, if i don´t put nothing in onConnection, it´ll work fine.

but the OnRecive method never is called, Then, i can´t process it.

moreover, the client only can send 5 messages. Unsure | :~

Re: I can´t understand why it doesn´t work

Joaquín M López Muñoz14-Apr-03 6:17

Joaquín M López Muñoz

14-Apr-03 6:17

Ummm... you have to call accept anyway, what's wrong with your code is not that, but the fact that the socket you use for accepting goes out of scope before its time has come.
Try dynamically allocating the socket as in

SurSocket2* ps=new SurSocket2;
Accept(*ps);

This will probably work, though it generates leaks (no one deletes ps). It is your job to implement some mechanism to track the accepted sockets and delete them when appropriate.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: I can´t understand why it doesn´t work

Martin_Viet14-Apr-03 7:01

Martin_Viet

14-Apr-03 7:01

It doesn´t work too. The client can connect and send the message whitout any error. But when i´m debuging the server , the Onconnect and OnRecive are never called.... The Client application work very well.

Re: I can´t understand why it doesn´t work

Joaquín M López Muñoz14-Apr-03 7:24

Joaquín M López Muñoz

14-Apr-03 7:24

Ok, try issuing ps->AsyncSelect(FD_READ|FD_CLOSE); after accepting.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: I can´t understand why it doesn´t work

Martin_Viet14-Apr-03 9:04

Martin_Viet

14-Apr-03 9:04

Sory Joaquin. but it doesn´t work too.(Pero sigue sin funcionar)

I can´t understand how can the client connect and send the message(only 5) if the server doesn´t accept the connection request? Mad | :mad:

Can it be a problem with events and messages in the main windows? should i define a windows partner ?

I´ll continue trying. Frown | :(

Anyway. Thank you very much Wink | ;)

el hombre arriesga su vida cada vez que elige y eso es lo que lo hace libre

Re: I can´t understand why it doesn´t work

Martin_Viet14-Apr-03 12:21

Martin_Viet

14-Apr-03 12:21

Everything was my mistake. because i had to overwrite OnAccept Method, not the OnConnect method. Dead | X|

I´m very stupid, sorry;P

el hombre arriesga su vida cada vez que elige y eso es lo que lo hace libre

pragma once

ns14-Apr-03 5:15

14-Apr-03 5:15

If I put pragma once in all my .h files that is sufficient to prevent any include multile definition problems right? Is this the same thing as doing #ifndef #define #endif that we see in the MFC .h generated files? If so , pragma once is much easier, so why isnt that used by t he Class wizard instead of the ifndef stuff?

Appreciate your help,
ns

Re: pragma once

User 988514-Apr-03 5:17

User 9885

14-Apr-03 5:17

In VC7, generated headers have only the

#pragma once

line.

My article on a reference-counted smart pointer that supports polymorphic objects and raw pointers

modified 29-Aug-18 21:01pm.

Re: pragma once

Joaquín M López Muñoz14-Apr-03 5:22

Joaquín M López Muñoz

14-Apr-03 5:22

As you say, both alternatives are equivalent. #pragma once, on the other hand, is not standard C or C++, so in general I prefer the #ifndef guard. As MS guys usually don't bother about standard compliance, I guess they don't use #pragma once only for historical reasons.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

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