C / C++ / MFC

Re: saving and loading application settings

7-Jul-03 13:12

Normaly I would search through the MSDN library first.

There is more than one article (+code) at codeproject.

To find the aticles just do the following:
1) In the search text box type in "registry",
2) Select "Titles" from the combobox.

Trust in the code Luke. Yea right!

John M. Drescher7-Jul-03 13:31

John M. Drescher

7-Jul-03 13:31

The registry it the recommended way unless there are more than 2K of INI settings. Either INI file or registry do not keep the data from the user unless you encrypt the data.

John

getting the value of an int in a cpp file into another

keegan7-Jul-03 9:51

keegan

7-Jul-03 9:51

any suggestions? i have an integer set equal to the value of GetCurSel(). i need to use this value in multiple functions, which i have spaced out over different header files. is there a way to acces this one value from all my other files? I've searched the msdn library for info on #ifndef, but i took away the impression thats solely for creating namespaces, which i think might be a little too far out of what i need to do.

thanks,

keegan

*.*

Re: getting the value of an int in a cpp file into another

Navin7-Jul-03 9:59

Navin

7-Jul-03 9:59

You could use a global variable, but that's icky.

What you ought to do is declare that integer as a static member variable in a class, and include the header for that class in any CPP that needs it.

e.g. (note, this is just to show the idea how it's done, you should probably have accessor functions instead of making it a public member, but that's beside the point)

(MyClass.h)
class MyClass
{
public:
   static int bob;
...
};

(MyClass.cpp)
// Need this to compile
int MyClass::bob = 0;
...

(SomeOther.cpp)
#include "MyClass.h"

...
void SomeFunc()
{
  int number = MyClass::bob;
  ...
}

"When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute and it's longer than any hour. That's relativity." - Albert Einstein

Re: getting the value of an int in a cpp file into another

keegan7-Jul-03 10:11

keegan

7-Jul-03 10:11

welp, i gave that a shot, but im getting unresolved external linker errors. i have mine set up exaclt like yours, the only difference is instead of SomeOther.cpp, i have SomeOther.h (figuratively speaking) i dont think that should make a difference...im including the header files in both places. when i say int MyClass::bob = 0; i get a linker error, and also when i try int number = MyClass::bob;.

any suggestions? i've double checked to ensure im including the header file with the declaration of my static int.

*.*

Re: getting the value of an int in a cpp file into another

John R. Shaw7-Jul-03 10:05

Re: getting the value of an int in a cpp file into another

7-Jul-03 10:05

You do some thing like the following:

extern int g_iMyCurSel;

This can be placed in a header file or source file as long as it is defined in at least one source file. If you wish to place it in several different header files then I would recommend some thing like the following be placed in each one:

// Just in case
#ifndef __G_IMYCURSEL__
#define __G_IMYCURSEL__
extern int g_iMyCurSel;
#endif

Trust in the code Luke. Yea right!

keegan7-Jul-03 10:16

keegan

7-Jul-03 10:16

this too gave me unresolved external symbols.

i put

extern int g_iMyCurSel;

into my header file,

//above the includes in my cpp file
#ifndef __G_IMYCURSEL__

//after the includes in my cpp file
#define __G_IMYCURSEL__
extern int g_iMyCurSel;

//somewhere in my cpp file...
g_iMyCurSel = 0;

//at the end of my cpp file
#endif

this gave me error, linker errors at that. Frown | :(

*.*

Re: getting the value of an int in a cpp file into another

John R. Shaw7-Jul-03 10:41

7-Jul-03 10:41

1) This is for use in your header files if and only if you wish to declare the same external variable in multiple header files. You would use it as it appears.

// Start of MyHeader.h
... // unknown code here
#ifndef __G_IMYCURSEL__
#define __G_IMYCURSEL__
extern int g_iMyCurSel;
#endif
... // unknown code here
// End of MyHeader.h

2) If you are going to declare it in 1 and only 1 header file then use:

// Start of MyHeader.h
... // unknown code here
extern int g_iMyCurSel;
... // unknown code here
// End of MyHeader.h

If you only want to declare it only in .cpp file but it needs to be accessed inline inside 1 or more header file then you must do the following before including those header files:

// Start of MyCPPFile.c
... // unknown code here
extern int g_iMyCurSel;
#include "MyHeaderFile.h" // header needing g_iMyCurSel
... // unknown code here
// End of MyCPPFile.c

Trust in the code Luke. Yea right!

Re: Simpler answer

John R. Shaw7-Jul-03 10:59

Re: getting the value of an int in a cpp file into another

7-Jul-03 10:59

1) Create a header file for the module (.cpp file) containing the global variable.
2) Declare the variable as follows in the header file for your module (.cpp file) as follows:
extern int g_iMyCurSel;
3) Include the header file for your module (.cpp file) before any other header files that needed to have access to your global variable.

Now any file that includes you modules (.cpp files) header file will have access to you global variable.

Trust in the code Luke. Yea right!

Michael Dunn7-Jul-03 17:19

Michael Dunn

7-Jul-03 17:19

See the FAQ
6.2 How do I share a global variable among my .CPP files?[^]

--Mike--
"I'm working really, really fast at the moment, so a 3 minute outage becomes, due to time dilation, a 5 minute outage."
-- Chris Maunder, relativistic system administrator
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber

Re: getting the value of an int in a cpp file into another

Terry O'Nolley10-Jul-03 9:13

Terry O'Nolley

10-Jul-03 9:13

If there is a true need for it and you comment it then why not use a global?

There is a reason why global variables work.

Lots of people blindly assume that globals are "BAAAAAAAD!!!!" but if that variable is truly needed across multiple source files then just use a global and be done with it.

Buuuuuuuuuuuuuuuuuuuuuut - 99% of the time the reason you now "need" a global is that there is some structural faults with the design of your application.

I'm going to live forever or die trying!

how to know if the VB function is part of COM object?

mr20037-Jul-03 9:47

How to use VB functions in VC program

7-Jul-03 9:47

Hi How can I know that a set of VB function is part of COM object?

Ehsan Behboudi

firewall project

ub817-Jul-03 9:10

ub81

7-Jul-03 9:10

i need to develop a basic firewall in vc++ which will restrict access to all ports except port 80. how should i go about it?

Re: firewall project

Dave Kreskowiak7-Jul-03 9:12

Dave Kreskowiak

7-Jul-03 9:12

Why go thru the hassle? If closing off everything but port 80 is what you want, why not just use a commercially available product?

RageInTheMachine9532

Re: firewall project

basementman7-Jul-03 15:56

basementman

7-Jul-03 15:56

Or, using W2K and XP, you can do port filtering right within the network driver setup.

onwards and upwards...

mr20037-Jul-03 9:10

7-Jul-03 9:10

Hi I am working with several hardware, some of them support VC++ and others support VB.

Is there any way I could write a VC++ program and be able to call VB function in that as well?

Thanks

Ehsan Behboudi

AlexO7-Jul-03 9:11

AlexO

7-Jul-03 9:11

If VB function is part of COM object yes, otherwise no.

mr20037-Jul-03 9:14

7-Jul-03 9:14

How can I check that out?
I don't know much about COM object

The VB code is to control motion control/data aquisition hardware.

Ehsan Behboudi

Shaffiq7-Jul-03 18:26

Shaffiq

7-Jul-03 18:26

hi,

You Can Use VB Functions In VC++ Program From VB Activex Dll. First Create VB Activex Dll as VB-GlobalMultiUse
Then Call VB Activex Dll From VC++

Leo12

mr20038-Jul-03 7:32

8-Jul-03 7:32

how can I make a VB activeX DLL in .NET?

Ehsan Behboudi