C / C++ / MFC

5-Apr-08 3:28

Hi. Any body could please advise on how to implement a simple c++ instruction to prevent another instance of the same program that is already running from being executed.
Many thanks

rp_suman5-Apr-08 4:13

5-Apr-08 4:13

You can use Mutex to do single instance check.

An article here: How to limit 32-bit applications to one instance in Visual C++[^]

Thanks,
Suman Smile | :)

--
"Programming is an art that fights back!"

J_E_D_I5-Apr-08 4:42

5-Apr-08 4:42

Excellent advice, it seems very well explained. Are we sure it comes from microsoft?? OMG | :OMG:

J_E_D_I5-Apr-08 21:25

5-Apr-08 21:25

I tried but it doesn't work. For it to work you'll need to use the old syntax (/clr:oldSyntax), which is incompatible with my application which uses a static library rather than dlls.
Thanks anyway

Jim Crafton5-Apr-08 4:48

Jim Crafton

5-Apr-08 4:48

rp_suman's link is good, but there's a better article here on CP http://www.codeproject.com/KB/cpp/avoidmultinstance.aspx[^]
This is particularly good to read if you have a GUI for your app.

J_E_D_I5-Apr-08 21:33

5-Apr-08 21:33

Thanks, but it seems a bit complex for me.. D'Oh! | :doh:

Is there an alternative without having to use an object?
I'm relatively new to c++ and I haven't used objects in my program so far.

Jim Crafton6-Apr-08 4:39

Jim Crafton

6-Apr-08 4:39

Well in that case you've got a lot of reading ahead of you!
Yes, you can do this without using classes, *but* the core technique outlined in the article really is the only good way to do this, as it properly deals with concurrency issues that many of the other approaches don't deal with, at least for an app that has a GUI. If you don't have a GUI then you may not need something as sophisticated.

Gary R. Wheeler6-Apr-08 1:43

Gary R. Wheeler

6-Apr-08 1:43

Here's my solution:

/* MultipleInstance.h */
 
class MultipleInstance {
 
public:
 
    MultipleInstance();
    ~MultipleInstance();
 
    static bool Active();
 
private:
 
    static bool                 _Active;
 
    static bool                 _Initialized;
    static HANDLE               _Handle;
    static MultipleInstance     *_Instance;
 
};
 
/* MultipleInstance.cpp */
 
static MultipleInstance _MultipleInstance;
 
bool                MultipleInstance::_Active       = false;
 
bool                MultipleInstance::_Initialized  = false;
HANDLE              MultipleInstance::_Handle       = NULL;
MultipleInstance    *MultipleInstance::_Instance    = &_MultipleInstance;
 
MultipleInstance::MultipleInstance()
{
    if ((!_Initialized) && (this == _Instance)) {
 
        // create security descriptor to let all users access the semaphore
 
        SECURITY_DESCRIPTOR security_descriptor = { 0 };
 
        InitializeSecurityDescriptor(&security_descriptor,
                                     SECURITY_DESCRIPTOR_REVISION);
 
        SetSecurityDescriptorDacl(&security_descriptor,TRUE,NULL,FALSE);
 
        // create semaphore
 
        SECURITY_ATTRIBUTES security_attributes = { 0 };
 
        security_attributes.nLength              = sizeof(security_attributes);
        security_attributes.lpSecurityDescriptor = &security_descriptor;
        security_attributes.bInheritHandle       = FALSE;
 
        SetLastError(0);
 
        _Handle = ::CreateSemaphore(&security_attributes,0,1,
                                    _T("Global\\InstanceSemaphore"));
                                    /* change "InstanceSemaphore" to your desired name */
 
        if (GetLastError() == ERROR_ALREADY_EXISTS) {
            _Active = true;
        }
 
        _Initialized = true;
 
    }
}
 
MultipleInstance::~MultipleInstance()
{
    if (_Initialized && (this == _Instance)) {
 
        if (_Handle != INVALID_HANDLE_VALUE) &&
           (_Handle != NULL)) {
 
            CloseHandle(_Handle);
            _Handle = NULL;
 
        }
 
    }
}
 
bool MultipleInstance::Active()
{
    return _Active;
}

Software Zen: delete this;
Fold With Us![^]

J_E_D_I6-Apr-08 19:55

Get how much bytes transferred CFTPConnetion and PutFile()

6-Apr-08 19:55

Hi, many many thanks for the advice but not being familiar to oject programming I am missing some crucial bits to make it work.

In MultipleInstance.h what name should I give to:
#ifndef
#define
Is there anything else I need to specify?

In MultipleInstance.cpp I have specified:
#include <iostream>
#include "MultipleInstance.h"
Is anything else needed?

In the main cpp file:
What is the correct syntax I need to use to call the object?
Should I insert it immediately after
int _tmain(int argc, _TCHAR* argv[]){

chetanjoshi95-Apr-08 1:49

chetanjoshi9

5-Apr-08 1:49

I am using CFTPConection class.
While uploading file via PutFile() function I also want to display
the destianion file size i.e. data uploaded up to perticaulr instant.

I could not make the connetion for that file as it is uploding i.e. it's open for writting.

So is there any way to check how much data transferred up to perticuar time. This value amy be in number of bytes.

Or is there is any othere option rather than Putfile() which uses buffer so that I can check buffer size..

please help me for this..

Thank you so much..

seting a blank date as the initial value for Date Time Picker control

Priya_Sundar4-Apr-08 22:51

Priya_Sundar

4-Apr-08 22:51

Hai all,

Can anyone suggest me how to set a blank date as the initial value for date time picker control?

I did as per the article : http://support.microsoft.com/kb/q238077/ [^]

I am currently using VC++ 6.0 and i get the following errors:
error C2039: 'SetCustomFormat' : is not a member of 'CDateTimeCtrl'
d:\program files\microsoft visual studio\vc98\mfc\include\afxdtctl.h(39) : see declaration of 'CDateTimeCtrl'

Is there any other way to do so?

Priya Sundar

Re: seting a blank date as the initial value for Date Time Picker control

rp_suman5-Apr-08 4:30

Re: seting a blank date as the initial value for Date Time Picker control

5-Apr-08 4:30

Hi,

The steps 1,2,3 mentioned in top may be for MS Date Time Picker Activex control and steps 1 & 2 bottom could be for the Windows Date Time Picker.

You try the steps 1 & 2 at bottom.

Thanks,
Suman

--
"Programming is an art that fights back!"

Priya_Sundar8-Apr-08 21:59

Priya_Sundar

8-Apr-08 21:59

Still it didnt work after doing step 1 and 2.

And fyi.. the if we do setwindowtext with empty text, then in that case itself we dont set a blank date, instead the the control displays the current system time with a default format.

Priya Sundar

Re: seting a blank date as the initial value for Date Time Picker control

rp_suman11-Apr-08 3:46

marshall interface needed?

11-Apr-08 3:46

Hi,

If you have not yet solved the problem, please post it as new message again.

It will be better posting your code.

It may be a programming bug or VC++.

Have you tried other styles[^]other than DTS_SHORTDATEFORMAT?

It seems there are some problem already related with Datetimecontrol: DateTimePicker Format changes from Time to Short Date[^]

Thanks,
Suman

--
"Programming is an art that fights back!"

George_George4-Apr-08 21:33

4-Apr-08 21:33

Hello everyone,

When we have cross-apartment call (inside one process) from ... to ...,

1. STA --> MTA;
2. MTA --> STA.

In both cases we must use either GIT (global interface table) or CoMarshalInterThreadInterfaceInStream?

If call method on destination apartment through interface pointer of component of destination apartment directly is violation (bypass the above two methods)?

(for example, sharing raw interface pointer directly in global variable and call methods on interface pointer directly)

thanks in advance,
George

Eytukan5-Apr-08 7:57

Eytukan

5-Apr-08 7:57

George you've started learning COM ? Dangerous! You got rid of STL atlast? Or STL got rid of you? Big Grin | :-D

OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus

Best wishes to Rexx[^]

Maximilien5-Apr-08 14:33

Maximilien

5-Apr-08 14:33

Maximilien Lincourt
Your Head A Splode - Strong Bad

George_George6-Apr-08 15:45

6-Apr-08 15:45

Thanks Maximilien,

Any ideas to my original question?

regards,
George

George_George6-Apr-08 15:44

asynchronous and synchronous call between apartments

6-Apr-08 15:44

Hi VuNic,

I use STL, COM and ATL, and I am also learning C#. Any ideas to my original question?

regards,
George

George_George4-Apr-08 21:24

How can Fix Window size as Maximize?

4-Apr-08 21:24

Hello everyone,

Once I thought all calls across COM apartments (not inside apartment) are all synchronous call, now after study re-entrancy problem, I think I am wrong, at least STA to MTA call is asynchronous.

(Link to re-entrancy problem, http://www.codeproject.com/KB/COM/sta_issues.aspx)

After some study, I can not find a conclusion whether the 4 types of calls are synchronous or asynchronous. Here is my study result, please feel free to correct me if I am wrong?

1. STA --> STA, I think asynchronous;
2. STA --> MTA, I think asynchronous;
3. MTA --> STA, I think synchronous;
4. MTA --> MTA, I think synchronous.

thanks in advance,
George

Le@rner4-Apr-08 18:34

Le@rner

4-Apr-08 18:34

Hi all,

In SDI type of application how can show application in Maximize mode and Fix it.

i m using this "ShowWindow(SW_MAXIMIZE);" in .cpp file of application,but it is not working properly.

it show application in maximize but restore also.

please anyone help me for this.

Thanks in advance.

Re: How can Fix Window size as Maximize?

rp_suman4-Apr-08 21:57