C / C++ / MFC

Passing pointer to other process

7-Jul-08 2:54

Thanks.
My favourite troll is a bit angry because he's hungry... I've forgot his dish today.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

JMGIC4-Jul-08 5:17

JMGIC

4-Jul-08 5:17

I want to share some data (int var) between two application app0 and app1.

The app0 calls app1 thrugh a CreateProcess, being one of the parameters a string containing the memory address of the data which I want to share (strVar = & var).

However when I assign the addres of var to a new pointer in app1 (int * pvar1), although they point to the same memory address (pvar1 == & var), the variables are not the same (*pvar1 != var). Instead, what I obtain in *pvar1 is a very high number which I assume is an error.

Should this operation work or the fail is what you would expect in this kind of botch?

Thank you and kind regards

JMGIC

image processing toolkits | batch image processing

C^hris L^osinger4-Jul-08 5:23

C^hris L^osinger

4-Jul-08 5:23

JMGIC wrote:
Should this operation work

nope

sharing memory between processes is a bit more complicated[^] than that

JMGIC4-Jul-08 5:26

JMGIC

4-Jul-08 5:26

OK, that is what I supposed,
thank you for the link!

Iain Clarke, Warrior Programmer4-Jul-08 5:38

4-Jul-08 5:38

I'd be cautious with the article - My reading of it is that it will only work if you have multiple instances of the same module / executable. That could work if you made a small DLL for both of your programs to use, but may be too much of a restriction.

Clever stuff, nonetheless.

Iain.

Plz sir... ^CPallini ^CPallini abuz drugz, plz plz help urgent.

Iain Clarke, Warrior Programmer4-Jul-08 5:34

4-Jul-08 5:34

I would expect it to fail spectacularly.

Each process has its own address space - which may map to an address in RAM, on the harddisk, etc. So an address valid in one process is (if you're *lucky*) invalid in another. If you're *unlucky*, it is valid but wrong in the other process.

I haven't been caught directly like this, but I did save structures to a file which used pointers. Which (oddly enough) weren't valid when I loaded them back later. The lesson was learnt.

There are a few ways of coping data about.

1/ WM_COPYDATA

2/ Mapped memory file.

3/ shared data segments, but this only works between processes using the same module, and can be very bad if you don't have to use it.

On the information you've given, I'd go for (2), where you could pass a number as a parameter and that as the name of a memory mapped file.

Iain.

Plz sir... ^CPallini ^CPallini abuz drugz, plz plz help urgent.

Converting existing VC++ Applications to be Compatible with Vista

JMGIC4-Jul-08 5:41

JMGIC

4-Jul-08 5:41

OK, thank you very much.
I will try to get some information about Mapped memory file.
Regards
JMGIC

NiceNaidu4-Jul-08 3:30

NiceNaidu

4-Jul-08 3:30

Hi All,
We have a project of converting the VC++ application to be compatible with Vista(as Administrator as well as Standard User).
The application should run successfully as Standard User.
The application consists of around 100 EXEs(Few run as services) and 200 Dlls and Ocxs .
So,we started identifying the areas that need to taken care like Registry, Messaging(SendMessage(), PostMessage()),CreateProcess(),GlobalObjects,Impersonation).

I have gone through so many links related to Vista(Esp. UAC).
But i have not found any link that gives the information regarding the conversion of legacy applications to Vista compatible.

Please post me any such link,so that i am not going to miss anything.

Thanks in Advance.

Appu..
"Never explain yourself to anyone.
Because the person who likes you does n't need it.
And the person who dislikes you won't believe it."

Re: Converting existing VC++ Applications to be Compatible with Vista

Mark Salsbery4-Jul-08 11:39

Mark Salsbery

4-Jul-08 11:39

The development guidelines you should have been following have been around since Windows 2000.
Only in Vista are they finally enforced.

Developer Best Practices and Guidelines for Applications in a Least Privileged Environment[^]

Also, search for the XP logo requirements document. There's a bunch of specific
stuff in section 3 (if I remember right) pertaining to proper registry and folder use.

Mark

Re: Converting existing VC++ Applications to be Compatible with Vista

NiceNaidu6-Jul-08 4:43

NiceNaidu

6-Jul-08 4:43

Thanks Mark.

Appu..
"Never explain yourself to anyone.
Because the person who likes you does n't need it.
And the person who dislikes you won't believe it."

Dialogbar shown as modal dialog

ilgale4-Jul-08 3:19

ilgale

4-Jul-08 3:19

Is it possible to show a CDialogBar as a modal dialog (I mean to be blocking) ?

If it is not possible... can I let the CDialogBar to be "a part"
of a CDialog ?

Thanks a lot!

How can I handle right-click of my application itself ?

SherTeks4-Jul-08 2:10

SherTeks

4-Jul-08 2:10

I have an end application (say Click.exe) which is placed on my desktop.

Now, I want to handle the Right click event of this exe itself ie.

if I right-click on the exe, I must be able to see a customized menu.

I know I don't have any control over the application Click.exe as such
because it is not yet started (ie. double-clicked).

Is this possible preferably by any VC++ way of handling events.

Any other solution like shell scripting ideas are also welcome.

Thanks in advance.

Re: How can I handle right-click of my application itself ?

Iain Clarke, Warrior Programmer4-Jul-08 2:25

Re: How can I handle right-click of my application itself ?

4-Jul-08 2:25

It's a rather brute force approach, but you could set a context menu handler (See Michael Dunn's superb shell series) for all exe, but only bother putting up for option if the file being right clicked on is called click.exe.

There are weak points to the idea - renaming, must be at least a partial admin to install shell extensions, what if the user makes a shortcut for the exe [*]?

Iain.

[*] I have a suspicion that the system resolves shortcuts for extensions for this very reason, but you'd have to check.

Plz sir... ^CPallini ^CPallini abuz drugz, plz plz help urgent.

Nibu babu thomas4-Jul-08 2:37

Nibu babu thomas

4-Jul-08 2:37

SherTeks wrote:
Now, I want to handle the Right click event of this exe itself ie.

if I right-click on the exe, I must be able to see a customized menu.

Is this what you are look for...

http://www.codeproject.com/KB/shell/shellextguide1.aspx[^]

Nibu babu thomas
Microsoft MVP for VC++

Code must be written to be read, not by the compiler, but by another human being.

Programming Blog: http://nibuthomas.wordpress.com

Increase number of files that can be opened

Amit4u4-Jul-08 1:41

Amit4u

4-Jul-08 1:41

in windows,
how do i set maximum open number of files ?
i tried to set FOPEN_MAX in stdio.h file, but it's not working....
need help....
thanks in advance...

xyz

vineeshV4-Jul-08 1:57

vineeshV

4-Jul-08 1:57

override the definition of FOPEN_MAX in your code not in stdio.h
as
#deinfe FOPEN_MAX <n> //n is the value you need to set .

vineesh

CPallini4-Jul-08 2:09

4-Jul-08 2:09

Do you really think such a #define will be of any help?
Smile | :)

vineeshV4-Jul-08 2:46

vineeshV

4-Jul-08 2:46

The actual definition of FOPEN_MAX in stdio.h
is

#define FOPEN_MAX 20

you can extend it to some limit (around 500)

The below code works fine

#include <stdio.h>
#include <windows.h>
#define FOPEN_MAX 500

FILE *stream, *stream2;

int main( void )
{
int numclosed;
int fd =3;

while (fd <= FOPEN_MAX)
{
if( (stream = fopen( "E:\\new.txt", "r" )) == NULL )
{

printf( "The file was not opened\n [%d] ",GetLastError());
getchar();
}
else
{
fd = fileno(stream);
printf( "The file was opened and fd is [%d] \n " ,fd);

}
}

numclosed = _fcloseall( );
printf( "Number of files closed by _fcloseall: %u\n", numclosed );

return 0;
}

============

vineesh

CPallini4-Jul-08 2:55

4-Jul-08 2:55

I don't get the point of doing that. Please see here [^] (as Iain explained very well the real purpose of FOPEN_MAX).
Smile | :)

vineeshV4-Jul-08 3:21

vineeshV

4-Jul-08 3:21

Yes Iain was correct ...

The actual libary code restrict the number of file open to 510 (i dont know the exact value ..).But normally the system will not allow you to open more than 20 files from a process .This is because of the FOPEN_MAX set to 20 in the header stdio.h .
#define FOPEN_MAX 20
We can only change the value below 510 .
#define FOPEN_MAX 510 //upto this will work
that means
#define FOPEN_MAX 511 may not work as it trying to override the max limit in the actual libray code

We cannot open infinite number of files using fopen ,but still we can extend the limit set in the stdio.h file as above .

The usage of CreateFile is an absolute replacement for fopen if you need to open file more than 500 times from a single process.

vineesh

CPallini4-Jul-08 2:07

4-Jul-08 2:07

Why do you think you can set it?

Iain Clarke, Warrior Programmer4-Jul-08 2:28

4-Jul-08 2:28

The limit will be in the actual library code - the constant in the header is just to let you know about the limit.

You may be able to recompile your own version of the libraries with a higher max value, but there may be other factors causing the limitation.

Or you could use API functions like CreateFile instead. The limit for that is "May as well be infinite. If you need to know the actual limit, you're in bigger trouble than you think".

Iain.

Plz sir... ^CPallini ^CPallini abuz drugz, plz plz help urgent.

C++ ATL DLL Addin for Windows Mail is blocked by Vista's DEP

Randor 4-Jul-08 5:54

Randor

4-Jul-08 5:54

http://msdn.microsoft.com/en-us/library/6e3b887c(VS.80).aspx[^]

http://msdn.microsoft.com/en-us/library/xt874334(VS.80).aspx[^]

http://www.codeproject.com/script/Forums/View.aspx?fid=1644&msg=2504818[^]

Best Wishes,
-David Delaune

dolly4-Jul-08 1:34

dolly

4-Jul-08 1:34

Hello Friends,

I am using Windows Vista and I am builing an c++ ATL DLL in Visual C++ 6.0, which is an addin DLL for Windows Mail. (Outlook Express)

When I run my Windows Mail, Vista's DEP (Data Execution Prevention) feature blocks it, and prompts that it blocked for security purpose as some other program tried to use windows mail data.

But I have to hook into Windows Mail as have to put an addin to customize its GUI.

I tried to turn DEP off for Windows Mail, but it didnt allow me (even in Full Admin Account).
Also I turned DEP off for my exe (which loads my addin DLL, which further hooks into Windows Mail), but despite that Windows Mail is blocked.

Also, when I build the project in Visual Studio 2005, it runs very well. (And I have not made any change in the project settings or code)

It seems, VC 6 uses older compilers and VS 2005 uses latest ones so are compatible with Vista!

But I have to use VC 6 only as it's my project's requirement!

Please Help!

Thanks a lot !!

dolly,
N,IN

Re: C++ ATL DLL Addin for Windows Mail is blocked by Vista's DEP

Iain Clarke, Warrior Programmer4-Jul-08 2:38