C / C++ / MFC

Re: How to establish a server in C++ : IP address issue

17-Mar-09 23:19

10.1.1.2 appears to be your internal networks address for your pc, as you suspect

Im guessing with 60.240.xxx.xxx you're going out to the internet through some gateway/proxy and thats what the public world sees

To get an address like 60.240.xxx.xxx to 'point' toward your machine, you need to 'NAT' [N]etwork [A]ddress [T]ranslate it (sometimes done on the firewall or switch or ... ) to a 10.1.1.x address - possibly a virtual i/p addres, thats what you'd be listening on ...

(hopefully someone else can fill in the gaps)

'g'

Iain Clarke, Warrior Programmer18-Mar-09 0:25

Iain Clarke, Warrior Programmer

18-Mar-09 0:25

Good thinking on using www.whatismyipaddress.com - I remember the site now, but I probably wouldn't have remembered if / when I needed.

If you do ipconfig /all, you'll see you have a Gateway address. Let's pretend that it is 10.1.1.1 (and quite likely too).

Your PC has an address of 10.1.1.2. When you want to talk to www.WIMIPA.com, your request first goes to 10.1.1.1. Assuming you are a small office, your router will be a NAT device, and have an outside world address of 60.240.xxx.yyy.

So, that website thinks the request is coming from the router - which it is. The router is clever enough to send the reply back to 10.1.1.2.

That's sending a request to the world.

For the other direction, it's a bit harder. You ask a DNS provider for www.includej10.com. You ask them to map that to 60.240.xxx.yyy. A.N.User asks that address that address for a webpage. The router then goes "huh? I'm not a webserver!" and fails to give a reply. OR: You can setup the router to say "Any traffic on port 80, please send that to 10.1.1.2 to handle". This is called port forwarding.

There are other wrinkles...

1/ If this is a small office, you may only have one router between you and the world. But your ISP may not give you the same IP address every time. This is tricky. There are services like dyndns that can help.

2/ If it's a larger office, you might have more than one router between you and the world, not to mention corporate firewalls. In which case, either get very friendly with your IT people, who'd better know more about this stuff than me, or tough.

3/ There's a reason people pay for webhosting... It makes a lot of this easier.

As for establishing a server for US users, the internet is nice and global - it's the same for Mongolian users also. If you have a lot of traffic, you might want to be physically closer, but the technology is the same.

I hope that helped a bit!

Iain.

In the process of moving to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), give me a job!

Linking library help.

FISH78617-Mar-09 14:42

FISH786

17-Mar-09 14:42

I have created a solution with 2 projects in it. One is a User Interface and the Second is a DLL. I have been able to compile both on their own with no problems.

However when I go into dependencies and make the User Interface dependent of the other, followed by a clean and trying to rebuild. I am able to get the DLL to compile and the user interface errors out trying to find the LIB of the DLL. What setting do I have to change or set to create the Lib file for the DLL.

Please Help.

thanks a million.

Garth J Lancaster17-Mar-09 16:11

17-Mar-09 16:11

Cant remember if it depends on 'what type' of dll .. there are generally two methods :-

the ?newer method - use the __declspec( dllexport ) declarator (see http://msdn.microsoft.com/en-us/library/3y1sfaz2(VS.80).aspx[^])

The older one (but I still use it) .. is to create a '.def' file which the linker uses to export the symbols .. this is the reference http://msdn.microsoft.com/en-us/library/d91k01sh(VS.80).aspx[^]

hth, 'g'

FISH78617-Mar-09 16:31

FISH786

17-Mar-09 16:31

I have the lines in my DLL.h file. I even took the Dllname.dll and put it in the Userappsource code directory. I even have the include for the header file. I guess that tells me it did find the header file to include so i put everything in the same directory as the header file as well. and in the bin directory of the User app. I just can't find the lib file that the user app is looking for.

This is what i already have in my header file.

#ifdef TESTHOOK_EXPORTS
#define TESTHOOK_API __declspec(dllexport)
#else
#define TESTHOOK_API __declspec(dllimport)
#endif

extern "C" TESTHOOK_API bool InstallHook();
extern "C" TESTHOOKHOOK_API void UninstallHook();

Garth J Lancaster17-Mar-09 17:05

17-Mar-09 17:05

Im going to ask what could be construed as obvious ...

you do have a define for TESTHOOK_EXPORTS dont you ?

ie,

#define TESTHOOK_EXPORTS

or (from memory) /D "TESTHOOK_EXPORTS" in your project options ..

in VC6 Blush | :O

when you're creating a dll you get a 'library' tab under project options, I wonder if its the same for whatever compiler you're using - you can define output options there

FISH78617-Mar-09 17:51

FISH786

17-Mar-09 17:51

I am a begginer with this barely being able to crawl. So please bare with me. I am using Visual Studio 2008. when I created my project for the DLL i did chose the options for the export. short of changing the dependencies and Unicode options I haven't changed anything else.
I am way behind in what I am trying to achieve. Instead of me reposting the whole thing. Do you mind reading my question on How to get multiple handles of the same class. Superman has been helping me with a lot. and I just replied him with my problems on there too. If either of you can help I will appreciate it a lot. I am trying to solve one issue and was given two different routes tried them both and stuck with both in different ways.
If you could read that article i will appreciate all the help.

thanks for all the help. Its greatly appriciated.

Digita Stop Watch

Astitva2317-Mar-09 14:17

Astitva23

17-Mar-09 14:17

I am building a simple quiz program and I want to implement an Stop Clock that basically starts counting from say 00:30 to 00:00. Can anyone give me some ideas or places to look for information for this implementation.

Re: Digita Stop Watch

Garth J Lancaster17-Mar-09 14:32

Showing an image to the use

17-Mar-09 14:32

as it happens, yes (although you could have searched for and found it yourself) ..

http://www.codeproject.com/KB/applications/xtimer.aspx[^]

Written by a well known/respected member of CP Smile | :)

'g'

llp00na17-Mar-09 11:21

17-Mar-09 11:21

Hi guys,

I have got an urgent question which I need to solve,
Plzzz this is very urgent, my whole dissertation depends on it, can you provide guidance? Deadline is Thursday afternoon.

I have created an MFC application (dialog-based), added a Picture control to the dialog in order show images (.bmp) to the user.

Now I am trying to display the images which the user selects in a scrollable area(for which i added a CScrollView). The application works fine when I capture screenshots manually using printSc and paste them in Paint, however I want the system to automatically capture screenshots and display them. The system indeed saves the image into the hard drive but fails to show to the user.

I am getting Debug Assertion Failed!

<br />
// This method captures a screen shot of the current page<br />
void CDetectChangeDlg::CaptureInstantPage()<br />
{<br />
  RECT rc;<br />
  HWND hWnd = m_webBrowser.GetSafeHwnd();<br />
  ::GetWindowRect (hWnd,&rc); <br />
  HDC hDC = ::GetDC(0);<br />
  HDC memDC = ::CreateCompatibleDC ( hDC );<br />
  HBITMAP memBM = ::CreateCompatibleBitmap ( hDC, rc.right-rc.left-20, rc.bottom-rc.top );<br />
  ::SelectObject ( memDC, memBM );<br />
  ::BitBlt( memDC, 0, 0, rc.right-rc.left-20, rc.bottom-rc.top, hDC, rc.left, rc.top , SRCCOPY );<br />
<br />
  char* imageName = (char*)"InstantImage.bmp"; // A screen shot of the current page<br />
  AnotherWayToSaveBitmap(imageName, memBM);<br />
  //SaveBitmap(imageName, memBM); // This way does not work<br />
<br />
  ::DeleteObject(memBM);<br />
  ::DeleteObject(memDC);<br />
  ::ReleaseDC( 0, hDC );<br />
}<br />
<br />
void CDetectChangeDlg:: AnotherWayToSaveBitmap(char *name,HBITMAP hBitMap)<br />
{<br />
	CBitmap bmp;<br />
	bmp.Attach(hBitMap);<br />
<br />
	BITMAP bitmap;<br />
	bmp.GetBitmap(&bitmap);<br />
	int size = bitmap.bmWidth*bitmap.bmHeight*bitmap.bmBitsPixel/8;<br />
	BYTE *lpBits = new BYTE[size];<br />
<br />
	::GetBitmapBits(hBitMap,size,lpBits);<br />
	WriteBmp(name,&bitmap,(int*)lpBits);<br />
	delete []lpBits;<br />
}<br />
<br />
<br />
// Show the image to the user<br />
void ManualImageSegmenterDlg::DisplayImage(CString strFileName)<br />
{<br />
	imageScrollView->m_Bitmap.DeleteObject();<br />
<br />
	HBITMAP hBmp = (HBITMAP)LoadImage(AfxGetInstanceHandle(), strFileName, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);<br />
	imageScrollView->m_Bitmap.Attach(hBmp);<br />
	<br />
	BITMAP bm;<br />
	imageScrollView->m_Bitmap.GetBitmap(&bm);<br />
	imageScrollView->m_sizeBmp = CSize(bm.bmWidth, bm.bmHeight);<br />
	imageScrollView->SetScrollSizes(MM_TEXT, imageScrollView->m_sizeBmp);<br />
	imageScrollView->Invalidate();<br />
}<br />

llp00na

CPallini17-Mar-09 11:32

CPallini

17-Mar-09 11:32

llp00na wrote:
Plzzz this is very urgent

You know that makes your question becoming a low-low-low priority one... Roll eyes | :rolleyes:

llp00na wrote:
I am getting Debug Assertion Failed!

What is the asserting line? Did you give a look at the stack calls window?
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]

llp00na17-Mar-09 11:44

17-Mar-09 11:44

I am really deseparate, my future depends on that

Assertion line is: imageScrollView->m_sizeBmp = CSize(bm.bmWidth, bm.bmHeight);

This also happens if I try to show jpgs and other formats. It could be something to do with the format of the image and the CScrollView.

No I did not, It's been a while since I programmed. So i dont know how to use the stack calls window

llp00na

CPallini17-Mar-09 11:57

CPallini

17-Mar-09 11:57

llp00na wrote:
I am really deseparate, my future depends on that

Sorry about...

llp00na wrote:
Assertion line is: imageScrollView->m_sizeBmp = CSize(bm.bmWidth, bm.bmHeight);

What is exactly the assertion message?
Smile | :)

llp00na17-Mar-09 12:01

17-Mar-09 12:01

it is debug assertion failed
Program: ....\DetectChange.exe
File:.......\include\afxwin1.inl
Line: 221

For more info
(Press retry to debug)

So i pressed retry and got:

Unhandled exception at mfc71d.dll in DetectChange.exe:
User breakpoint

llp00na

bulg17-Mar-09 12:04

bulg

17-Mar-09 12:04

The api that you're using to load the bitmap returns 0 if it failed to load. why don't you do some error checking??? (if statements)
if you're averse to that, then step through it (insert a breakpoint before you load, then run it, then press f10 and f11 to step through or step into lines, typing in variable names in the QuickWatch window to see what values are what).

llp00na17-Mar-09 12:27

17-Mar-09 12:27

I tried

if (hBmp != 0){
}

I still got the same error message

ANy more ideas

llp00na

CPallini17-Mar-09 13:10

CPallini

17-Mar-09 13:10

It's OK. It would be even better if you reply to the right post. Big Grin | :-D

bulg17-Mar-09 13:32

bulg

17-Mar-09 13:32

my bad, did it send you an email?

llp00na17-Mar-09 13:53

Bit for bit reproducible build in vc6.

17-Mar-09 13:53

Can you send you the code to inspect please ???

llp00na

_aesthetic_17-Mar-09 11:19

_aesthetic_

17-Mar-09 11:19

Heya folks.

I've been pulled into a vc6 project at the last minute. My particular task is to make a relatively large build reproducible, bit for bit, as it will be subject to auditing. The reason I was tasked with it is because I did this for another project a few years ago using MSVS 2003, but I've hit a wall with vc6.

The tl;dr version is, has anyone successfully done this with vc6? Moving to a newer tool chain isn't an option, as it's not my project.

We're building in a VM to minimize any environment differences. In the VM, we always build from the same directory, so that makes any source filenames pulled in via __FILE__ the same. As a post process, we walk the PE headers to find all of the timestamps in the file and set them to midnight, 2000-Jan-01. In the previous project, this was all that was needed. In that VM, running on any of the machines that we tested on, all builds of a particular revision would match.

Doing that with the vc6 project will work sometimes, but sometimes not. To really isolate any local differences, we have 2 machines with the same hardware using a cloned drive. Neither machine is on a network, so they don't have any collisions with each other. Because the drives are cloned, the VMs and VM executables are identical. When we put our source archive on the machine, we copy it via usb drive (same drive into the same respective usb port), unpack it, and then reboot. After rebooting, we run vc6, select our build target, and rebuild all. Running the build in this manner on these machines will sometimes produce different output. It's intermittent, but it only affects one of our 3 binary outputs. We also build a pthreads dll and shell process, and both of those always match after our timestamp fixups.

After some investigation, I'm pretty sure that the first issue (of many) is that cin, cout, and cerr (or their static constructors) are off by 3000h in the different builds. That's a huge problem, and it sounds like linker order. This project has thousands of files. Is it possible to specify their build and link orders short of a .bat file? Would that even work?

Using a binary diff of the two files, there is an area of about 1600 bytes starting at 001E41C0h (1982912) with sparse differences. Usually 1 or 2 bytes differ, then there is a string of 8-32 identical bytes. An example of the first diff, from VBinDiff, is

vm1.exe
001E 41A0: 68 80 F8 5D 00 E8 82 BD 01 00 59 C3 90 90 90 90 hÇ°].Φé╜ ..Y├ÉÉÉÉ
001E 41B0: E8 0B 00 00 00 E9 16 00 00 00 90 90 90 90 90 90 Φ....Θ.. ..ÉÉÉÉÉÉ
001E 41C0: B9 51 5C 77 00 E9 4A 10 01 00 90 90 90 90 90 90 ╣Q\w.ΘJ. ..ÉÉÉÉÉÉ
001E 41D0: 68 E0 41 5E 00 E8 52 BD 01 00 59 C3 90 90 90 90 hαA^.ΦR╜ ..Y├ÉÉÉÉ
001E 41E0: B9 51 5C 77 00 E9 A9 11 01 00 90 90 90 90 90 90 ╣Q\w.Θ⌐. ..ÉÉÉÉÉÉ
001E 41F0: E8 0B 00 00 00 E9 16 00 00 00 90 90 90 90 90 90 Φ....Θ.. ..ÉÉÉÉÉÉ
001E 4200: B9 50 5C 77 00 E9 E5 14 01 00 90 90 90 90 90 90 ╣P\w.Θσ. ..ÉÉÉÉÉÉ
001E 4210: 68 20 42 5E 00 E8 12 BD 01 00 59 C3 90 90 90 90 h B^.Φ.╜ ..Y├ÉÉÉÉ
001E 4220: B9 50 5C 77 00 E9 46 16 01 00 90 90 90 90 90 90 ╣P\w.ΘF. ..ÉÉÉÉÉÉ

vm2.exe
001E 41A0: 68 80 F8 5D 00 E8 82 BD 01 00 59 C3 90 90 90 90 hÇ°].Φé╜ ..Y├ÉÉÉÉ
001E 41B0: E8 0B 00 00 00 E9 16 00 00 00 90 90 90 90 90 90 Φ....Θ.. ..ÉÉÉÉÉÉ
001E 41C0: B9 21 5C 77 00 E9 4A 10 01 00 90 90 90 90 90 90 ╣!\w.ΘJ. ..ÉÉÉÉÉÉ
001E 41D0: 68 E0 41 5E 00 E8 52 BD 01 00 59 C3 90 90 90 90 hαA^.ΦR╜ ..Y├ÉÉÉÉ
001E 41E0: B9 21 5C 77 00 E9 A9 11 01 00 90 90 90 90 90 90 ╣!\w.Θ⌐. ..ÉÉÉÉÉÉ
001E 41F0: E8 0B 00 00 00 E9 16 00 00 00 90 90 90 90 90 90 Φ....Θ.. ..ÉÉÉÉÉÉ
001E 4200: B9 20 5C 77 00 E9 E5 14 01 00 90 90 90 90 90 90 ╣ \w.Θσ. ..ÉÉÉÉÉÉ
001E 4210: 68 20 42 5E 00 E8 12 BD 01 00 59 C3 90 90 90 90 h B^.Φ.╜ ..Y├ÉÉÉÉ
001E 4220: B9 20 5C 77 00 E9 46 16 01 00 90 90 90 90 90 90 ╣ \w.ΘF. ..ÉÉÉÉÉÉ

The first 3 diffs are different by 30h. Interpreting the diffs as bytes in an aligned 4-byte words, the first one is 775C51B9h vs. 775C21B9h, which is off by 3000h.

I don't have the output in front of me, but when we looked this offset up in CFF Explorer, it looked to be a jump table of sorts. It was something like
mov cx, (constant)
jmp (another constant)

Of these two constants, one matched and the other was the same diff above (775C51B9h vs 775C21B9h). I don't remember which was which off the top of my head, but I do remember what was at the target of the jumps. Following the jumps, and comparing it to a .map of the build, it looks to be the global static constructor table ($E18 or $E24, iirc). The first offending entry is the static constructor that sets up cin. The other two are cout and cerr.

The identical build machines are using an embedded celeron processor with a gig of ram running XP Pro Sp2. The VM is VMWare player, the most recent version, running XP Pro Sp2 and MSVC++ Enterprise Edition.

Does anyone have any insight? Thanks!

Re: Bit for bit reproducible build in vc6.

Garth J Lancaster17-Mar-09 12:03