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Moak wrote: (where APR traffic will not be forwarded but IP traffic will be
Nitpicking: BTW, that ought to be ARP traffic. 
“Follow your bliss.” – Joseph Campbell
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If you want to add a reply, keep it public. Do not delete it after you've posted something!
Workout progress:
Current arm size: 14.4in
Desired arm size: 18in
Next Target: 15.4in by Dec 2010
Current training method: HIT
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Hi Rajesh,
Thanks for the support. To be fair the recommendation made by Michel Godfroid is not incorrect. I was simply giving an alternative and optimized solution for scanning a local network. Allow me to give a more complete explanation.
Here is an exercise for the readers:
1.) Download a packet sniffer such as WireShark[^]
2.) Follow the advice Michel Godfroid gave and scan the entire local subnet. Monitor the Wireshark output.
Here is what you will see:
1.) You will first see an ARP broadcast generated by TCPIP.SYS for each attempted connection to a local IP address (if not already cached). If there is something there it will respond with an ARP reply.
2.) If a network device is on the other side you will then see the TCP handshake and connection attempt. If there is no device there winsock will return a Winsock Error Code[^].
The response I gave was cutting out the TCP protocol from the equation... Since we know the NDIS layer TCPIP.SYS will ARP for the address anyway... when scanning the local subnet.
Best Wishes,
-David Delaune
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Randor wrote: To be fair the recommendation made by Michel Godfroid is not incorrect.
I realise that, and actually his answer carries my 5 vote!
“Follow your bliss.” – Joseph Campbell
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Sure, the ARP broadcast is there
- to find the MAC address of the DHCP or BOOTP server in order to get an IP address if auto address configuration is enabled.
- to detect an available address if no DHCP or bootp servers are there, and automatic address assignment is in effect (169.254/16 network)
- to see if the assigned address is already in use on the network.
- if netbios is enabled, to get at the network neighbourhood machines (netbios is basically a layer 2 protocol)
- to find a master browser, and start the master browser election
- to find the default gateway
Otherwise I'm a bit bothered by your definition of LAN environment: can a LAN not include routers? In that case my home environment does not qualify as a LAN. Each virtual machine host includes a router to effect separation between in host-traffic and LAN Traffic. Any corporate environment, even in the 192.168 subrange will include routers, just because it's usually bad practice to put more than a couple of hundred hosts on a broadcast segment (and the default netmask is /24).
I use a 10/8 network at home, which I divide in /24 networks because of
- Megalomania
- I can't be bothered to calculate subnets which are not a multiple of 8 I suspects network admins out there are as lazy as I am.
modified on Monday, May 10, 2010 3:14 PM
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Hi Michel,
As I stated... your advice is not incorrect. I simply gave an alternative solution for scanning the local subnet for networked devices.
Lets have a beer and work on calculating subnets which are not a multiple of 8.
Best Wishes,
-David Delaune
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I admit I got a bit carried away. I have a thing with MAC addresses, and not using them for what they were designed  . A childhood trauma involving X25 probably.
Given the OP's initial statement (and not knowing the OP's level of knowledge), I thought your initial answer might confuse the issue. I concentrated on an answer which would work in every case.
Randor wrote: Lets have a beer
As soon as the ash clouds leave Europe...
Cheers!
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I try to launch an crystal report with CrystalCtrl , and succeed in this way :
#include "CrystalCtrl.h"
void CMainFrame::OnHelpLaunchreport()
{
try
{
GetSystemMenu(FALSE)->EnableMenuItem(SC_CLOSE,MF_GRAYED);
m_CrystalCtrl.SetReportFileName("autocolant.rpt");
CString sTitle = m_CrystalCtrl.GetReportFileName();
m_CrystalCtrl.SetWindowTitle(sTitle);
m_CrystalCtrl.SetWindowShowExportBtn(FALSE);
m_CrystalCtrl.SetWindowShowPrintSetupBtn(TRUE);
m_CrystalCtrl.SetWindowState(2);
m_CrystalCtrl.SetAction(TRUE);
GetSystemMenu(FALSE)->EnableMenuItem(SC_CLOSE,MF_BYCOMMAND);
}
catch(CException* pException)
{
pException->ReportError();
pException->Delete();
}
}
My questions is : if something bad is happening during try section , programs stop without any warning .... How can I catch exception ?
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When is talk about Crystal Report , is silence , avoid by everybody ... 
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mesajflaviu wrote: When is talk about Crystal Report , is silence...
Perhaps that's an indication that few, if any, use it.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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I don't mean something bad , is just an ... thought ... if I upset on somebody , forgive me ! You are always very kind , so I don't want to harm anybody !
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I doubt anyone's upset. I was just allaying your concern about not getting a response. There can be a multitude of reasons why folks do not answer questions.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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I want to know how a read/write calls is accomplished in linux?
I mean how a function say read() will read the data from a file.
What all will be the steps from user mode read() function call to kernel mode?
Will anybody explain the steps or let me know any site from where I can get this info?
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1) I suggest you post in the linux forum.
2) Since this is all open source stuff, I suggest you have a look at the stdio library source code.
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Thanks for the information.
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Hi,
All modern operating systems in protected mode [^]work nearly the same when executing privileged instructions. They all pass through a call gate[^] and allow the kernel to do the system call[^]. The modern system call instructions are SYSENTER/SYSEXIT. In the old days it was interrupt 0x2e in Windows and 0x80 in Linux.
Here is an example of a Win32 function which is written with both 0x2e and SYSENTER syntax.
http://www.codeproject.com/Messages/2468550/Re-Send-Key-Input.aspx[^]
To answer your question I would summarize as follows:
1.) Glibc simply pushes your arguments onto the stack and invokes the sysenter instruction. (An older version of Linux will invoke interrupt 0x80)
2.) When the CPU sees the SYSENTER instruction it will JMP to the address listed in the registered SYSCALL table. It will execute the instructions there. (Here is where permissions and actual I/O is performed)
Best Wishes,
-David Delaune
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5 from me, thanks!
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Great reply.
That clears it all.
Also find a good description of query at:
http://www.ibm.com/developerworks/linux/library/l-system-calls/
This reply is very much similar to the explaination for windows of read/write() as explained in the chapter IO systems of book Microsoft Windows Internals by Mark E. Russinovich and David A. Solomon
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Hi,
I am reposting same question again becuase I am not getting sathisfied answer.
I have a DLL which is having pure functions and virtual functions. Now what to do with that to define the virtual function in my own class?
How to use dll?
How to define virtual function?
Any example?
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As I said before, there's nothing special in using abstract classes coming inside a DLL.
I have done a little test:
#ifdef CPPDLL_EXPORTS
#define CPPDLL_API __declspec(dllexport)
#else
#define CPPDLL_API __declspec(dllimport)
#endif
class CPPDLL_API CCppDll
{
public:
CCppDll(void);
virtual int foo();
virtual int goo(int x)=0;
};
#include "stdafx.h"
#include "..\\..\\CppDll\\CppDll\\CppDll.h"
#include <iostream>
using namespace std;
class MyDer: public CCppDll
{
public:
int goo(int x){ return x*x;}
};
int _tmain(int argc, _TCHAR* argv[])
{
MyDer m;
cout << m.foo() << " " << m.goo(5) << endl;
return 0;
}
I compiles and works fine.
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]
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Thanks Pallini,
Let me check ...
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If I design simple dll having exported function, it works fine.
But when I put same function code in class and put the name in "Additional Dependency". I am getting fatel error:
fatal error LNK1107: invalid or corrupt file: cannot read at 0x2B0
I written below code for exported function
EXPORTS
sum @1
But to write for class.....confused...
Please dont mind If I am asking silly question...
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john5632 wrote: EXPORTS
sum @1
You must NOT do that for the class (you must NOT prevent name decoration). Just use the EXPORT macros (i.e. the CPPDLL_API in my example) Visual Studio provides for you.
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]
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I am getting the fatal error. I tell what I did:
I am able to create dll file with class.
1. Added .h file in my project
2. Make "Add Dependecy" for dll file in linker settings.
When I try to run, compiler says "invalid or corrupt file: cannot read at 0x2B0"
Code for dll (.h):
--------------------------------------------------------------------
#ifdef CPPDLL_EXPORTS
#define CPPDLL_API __declspec(dllexport)
#else
#define CPPDLL_API __declspec(dllimport)
#endif
// This class is exported from the CppDll.dll
class CPPDLL_API CCppDll
{
public:
CCppDll(void);
int sum(int a,int b);
//virtual int goo(int x)=0;
};
dll code for (.cpp)
----------------------------------------------------------
#include "stdafx.h"
#include "samdll.h"
int CCppDll::sum(int x , int y)
{
return x+y;
}
Am I correct?
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Well, you have to add the .lib file in the linker settings... 
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]
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