Re: BOOL to bool conversion - C / C++ / MFC Discussion Boards

J.B.4-Jul-04 6:39

J.B.

4-Jul-04 6:39

Hi guys,

as coming from a pure C++ programming background, I'm quite used to the use of boolean type bool and has decided to continue using it when developing MFC apps. From MSDN, I understood that bool type variable would occupy less memory than BOOL (1 bytes vs. 2 or 4 bytes), since BOOL is actually int type. Correct?

In my programs, I have some BOOL type DDX control value to be passed as function parameters. And when I did that, I get warning message like the following:

warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' (performance warning)

performance warning, doesn't sound very good to me Frown | :(

Is it better I do a conversion manually before passing it or that effort isn't generally required?

<code>
BOOL bTest;

if (bParameter == true)
	bTest = TRUE;
else
	bTest = FALSE;

Thanks!

Re: BOOL to bool conversion

User 66584-Jul-04 7:07

User 6658

4-Jul-04 7:07

BOOL is indeed a typedef'd int.

If you want to do a safe conversion do this:

bTest = (bParameter != FALSE);

I don't know what kind of performance decrease you get when directly casting a bool to a BOOL.

regards

modified 12-Sep-18 21:01pm.

Re: BOOL to bool conversion

Tim Smith4-Jul-04 7:12

Tim Smith

4-Jul-04 7:12

You have it backwards, the performance hit is when you do a BOOL to a bool.

bool bOut = bIn != FALSE;

BTW, with a BOOL, never do (x == TRUE) as a test. As far as conditionals go, it is 0 or not 0. It doesn't test for FALSE and TRUE.

Tim Smith

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

Re: BOOL to bool conversion

J.B.4-Jul-04 7:19

J.B.

4-Jul-04 7:19

Thanks alot guys,

the comments are very useful.

Tim, are you saying a BOOL type variable can be more than just TRUE (1) and FALSE (0) ?

Re: BOOL to bool conversion

User 66584-Jul-04 7:34

User 6658

4-Jul-04 7:34

actually, yes. But I've not seen any app setting the value of a BOOL to anything other apart from TRUE and FALSE.

TRUE is just a #define (1), while FALSE is a #define (0)

modified 12-Sep-18 21:01pm.

Re: BOOL to bool conversion

A T I F4-Jul-04 22:14

A T I F

4-Jul-04 22:14

Don;t be too sure about it... TrackPopupMenu return BOOL and it can be made to return which menu item was selected in the popup menu (setting via parameters).

Re: BOOL to bool conversion

User 66585-Jul-04 0:54

User 6658

5-Jul-04 0:54

Thanks; that's why I said "I haven't seen any app....". Now I know there IS at least one API doing such things Smile | :)

regards

modified 12-Sep-18 21:01pm.

Re: BOOL to bool conversion

Tim Smith5-Jul-04 4:03

Tim Smith

5-Jul-04 4:03

The WIN32 API is a bit of a minefield when it comes to BOOL processing. On NT the API might return a true TRUE/FALSE while on Win9x, then API might return ==0/!=0. This is why I always say to play it safe and never test for "== TRUE".

Tim Smith

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

Re: BOOL to bool conversion

V.4-Jul-04 22:18

4-Jul-04 22:18

if your BOOL > 0 it is TRUE.
if your BOOL = 0 it is FALSE.
Don't know for sure for values < 0.

their are apps eg. where your BOOL has value 2 or 3 , ...
then you can do if(YOURBOOL){ ... }

personally I think BOOL is against the whole idea of the basic datatype of a boolean. I would recommend a bool if you want to use true or false and an int or something if you have more values (and do if(yourint == 3){...})
but it's MFC Unsure | :~

"If I don't see you in this world, I'll see you in the next one... and don't be late." ~ Jimi Hendrix

Re: BOOL to bool conversion

Tim Smith5-Jul-04 4:01

Tim Smith

5-Jul-04 4:01

it is

BOOL == 0 is FALSE
BOOL != 0 is TRUE

Tim Smith

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

Using MFC in Win32 Application

vyjesh4-Jul-04 0:33

vyjesh

4-Jul-04 0:33

Hi Everybody,

I have a question regarding "Using MFC in Win32 Application". I am using Visual Studio6.0. I want to use MFC in my Win32 Application. I started File->New->Win32 Application->A Simple Win32 Application. And I get the following code pasted below. Now I want to use MFC, say, CString, How do I do it? I tried to use as "CString str" and included the header file <afx.h> but of no use. It gives compile errors as "CString undeclared identifier" Can anybody help? Can anybody tell me which header files and .lib files to use, or any other settings to be made to the editor???

----------------------------------------------------------
// FirstSample.cpp : Defines the entry point
// for the application.
//

#include "stdafx.h"

int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
// TODO: Place code here.
CString str;
return 0;
}
-----------------------------------------------------------

Regards
VYJU

Re: Using MFC in Win32 Application

gamitech4-Jul-04 6:19

gamitech

4-Jul-04 6:19

after:
am using Visual Studio6.0. I want to use MFC in my Win32 Application. I started File->New->Win32 Application->A Simple Win32 Application. And I get the following code pasted below.
click the "Project" menu
then choose Settings.
In the "General" tab you will see that you project ins't currrently using MFC. You can choose to use MFC in a static LIBRARY or in a DLL. I f you choose to have it in a library you'll have to include these files in stdafx.h
:
#include <afxwin.h> // MFC core and standard components
#include <afxext.h> // MFC extensions
#include <afxdisp.h> // MFC Automation classes
#include <afxdtctl.h> // MFC support for Internet Explorer 4 #include #include <afxcmn.h> // MFC support for Windows Common

I haven't used MFC in a dll and I don't know if you have to include them there but i know that you won't have to carry all those DLL's if you want to check your app on a computer without VC++ installed

gabby

Re: Using MFC in Win32 Application

Frank K4-Jul-04 19:34

Frank K

4-Jul-04 19:34

Hi,

File->New->Projects->MFC AppWizard(exe)

In the following dialogs you can choose some options.

HTH
Frank

problem with console app

cpeed4-Jul-04 0:29

cpeed

4-Jul-04 0:29

here is a relevent snippets:

TCHAR buf[20]; 

fdwMode = ENABLE_LINE_INPUT |       //ReadConsole() should wait and read 
                                   // characters until ENTER is pressed 
                 ENABLE_ECHO_INPUT |   // show characters as you type 
                 ENABLE_PROCESSED_INPUT;    // let system process all 
                                                // control keystrikes 
SetConsoleMode(hStdin, fdwMode) ; 
        
fdwMode = ENABLE_PROCESSED_OUTPUT; 
SetConsoleMode(hStdout, fdwMode); 


while (1) 
{ 
    WriteConsole(hStdout, "\npress [1] for codepage: ", 25, &ch, NULL); 
     ReadConsole(hStdin,buf,1,&ch,NULL); 
     buf[ch]='\0'; 
     FlushConsoleInputBuffer(hStdin); 
    WriteConsole(hStdout, buf, 3, &ch, NULL); 
}

the problem is that the first time while executes everything is ok:
i get on screen:

press [1] for codepage:

i enter 1 and press enter then it prints the character.

from this point something strange happens...
while loop continue to execute two more times despite the fact that ReadConsole() should wait for input...

anyone understand where is the problem?

Re: problem with console app

Mike Nordell4-Jul-04 1:17

Mike Nordell

4-Jul-04 1:17

cpeed wrote:
anyone understand where is the problem?

Considering you only request one char, and '1' + CR + LF is three chars...

Re: problem with console app

cpeed4-Jul-04 1:25

cpeed

4-Jul-04 1:25

but i using FlushConsoleInputBuffer() after call to ReadConsole()

and i using also ENABLE_PROCESSED_INPUT flag. the documantation says that in this case system processes the control keys and doesn't put them to input buffer
link

the "outp" command

Member 12178723-Jul-04 22:59

Member 1217872

3-Jul-04 22:59

TO: Michael Dunn.

Thank you for your answer.

Eng. Menahem Menasheroff

Re: the "outp" command

peterchen4-Jul-04 0:30

peterchen

4-Jul-04 0:30

please keep such replies in the thread of your question (i.e. reply directly to the helpful answer, do not create a new thread for this). Thank you.

we are here to help each other get through this thing, whatever it is Vonnegut jr.

sighist || Agile Programming | doxygen

the "outp" command

Member 12178723-Jul-04 22:56

Member 1217872

3-Jul-04 22:56

TO: Johan Rosengren

Thank you for your answer.

Eng. Menahem Menasheroff

the "outp" command

Member 12178723-Jul-04 19:24

Member 1217872

3-Jul-04 19:24

Hi.
I am trying, unsuccessing, to operate the outp command in C++ (Visual Studio
Ver 6.0) through the address of the printer.

I have an OS windows XP.

I wrote: "outp(0x378,0x24);" trying to operate the LPT1 address, and nothing
happened.

Please, show me how to do it rigth.

Thank you.
Eng. Menahem Menasheroff

Re: the "outp" command

Michael Dunn3-Jul-04 20:40

Michael Dunn

3-Jul-04 20:40

That call only works on Win 9x

--Mike--
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Re: the "outp" command

Johan Rosengren3-Jul-04 21:02

Johan Rosengren

3-Jul-04 21:02

You might want to check this section on MSDN: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/devio/base/communications_resource_handles.asp[^]

dialog box help

AmericanBacon3-Jul-04 15:15

AmericanBacon

3-Jul-04 15:15

Hi all,
I would like to open a dialog box from a console application. Basically, I have an app that looks for new processes and if certain processes appear I want to pop up a dialog box.
Any pointers to tutorials, articles, sample code would be appreciated.

-bacon

Re: dialog box help

Ravi Bhavnani3-Jul-04 16:04

Ravi Bhavnani

3-Jul-04 16:04

You may want to instead consider building a standard Windows app that runs in the system tray a la anti-virus, firewall and similar daemon apps.

/ravi

My new year's resolution: 2048 x 1536
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Re: dialog box help

PJ Arends3-Jul-04 17:22

PJ Arends

3-Jul-04 17:22

http://www.codeproject.com/dialog/consoledialogs.asp[^]

http://www.codeproject.com/win32/winconsole.asp[^]

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