::CreateFileMapping - C / C++ / MFC Discussion Boards

Paul M Watt10-Oct-02 6:17

10-Oct-02 6:17

I am sure there is probably a way to get that information, I am not sure how to get it though.

However, if you want the date in order to know whether you should download the file or not, you can add the If-modified-since header item, and then the server will only send the file to you if it has been modified since the date that you sent. If the server does not send you back a file then the return status code will be 304.

If you are using MFC here is the sample code that you would use with the CTime object. If you would like sample code for regular C/C++ let me know.

CString sFileDate;
sFileDate.Format("If-modified-since: %s\r\n", ctime.FormatGmt("%a, %d %b %Y %H:%M:%S GMT"));
Good Luck

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: Check date modified http request?

dazinith10-Oct-02 8:00

dazinith

10-Oct-02 8:00

how would i use this if-modified-since when requesting the file? currently i am just giving the location of the file on the web, and where i want to save it.. here is what i have, thanks!

hr = URLDownloadToFile( NULL,      // ptr to ActiveX container
                         sURL,      // URL to get
                         sFile,     // file to store data in
                         0,         // reserved
                         &callback  // ptr to IBindStatusCallback
                       );

still a newb.. cut me some slack :P
-dz

combobox that disappears over a listcontrol...

Joan M10-Oct-02 5:52

Joan M

10-Oct-02 5:52

Hello...

I need to show an editcontrol and a combobox over a listcontrol depending of the kind of edition that is allowed in the field that I want to modify...

(i.e: if I'm editing a field that can only have 3 possible values, the combo have to be shown, but if the field can get any value, then I need to show the editbox)

In order to do this I'm using an article readen in codeproject

http://www.codeproject.com/listctrl/editing_subitems_in_listcontrol.asp[^]

and my problem is that when I do the same that is explained in this article, I don't understand why the editcontrol and the combobox disappear...

I don't want the combo box to disappear, the editbox is OK...

any idea?

NOTE:
I've tried to set it topmost (using SetWindowPos), but it's the same...

As always thank you in advance...

Re: combobox that disappears over a listcontrol...

Roger Allen10-Oct-02 6:14

Roger Allen

10-Oct-02 6:14

My guess would be that you need to change the tab order of the edit/combo controls compared to the list control. They either have to be before or after it in the tab order. I forget which.

Roger Allen
Sonork 100.10016

I think I need a new quote, I am on the prowl, so look out for a soft cute furry looking animal, which is really a Hippo in disguise. Its probably me.

Re: combobox that disappears over a listcontrol...

Joan M10-Oct-02 6:30

Joan M

10-Oct-02 6:30

I hate when the solution is so simple...

I've invalidated the combobox...

but thank you for your interest!

Display Transparent AVI

Brigg Thorp10-Oct-02 5:49

Brigg Thorp

10-Oct-02 5:49

OK guys...I'm trying to display an AVI file on my dialog with a transparent background and I'm not having any luck,

I made an AVI file with a white background on each clip. I have an animation control on my dialog and I have both transparent properties set. When I go to play the AVI, I still see the white background.

Here is the function to create the control:

HWND CreateAnimationCtrl(HWND hwndDlg, int nIDCtl) 
{ 
  HWND hwndAnim = NULL; 
  RECT rc; 
  POINT pt; 
	
  // Create the animation control. 
  hwndAnim = Animate_Create(hwndDlg, IDC_ANIMATE, WS_CHILD, ghInst); 
	
  // Open the AVI clip, and show the animation control. 
  Animate_Open(hwndAnim, MAKEINTRESOURCE(IDR_AVI)); 
  ShowWindow(hwndAnim, SW_SHOW); 
	
  return hwndAnim; 
}

Here is what I call in the WM_INITDIALOG routine:

hAnim = CreateAnimationCtrl(hDlg, IDC_ANIMATE);
Animate_Play(hAnim, 0, -1, -1);

Do I have to do something special to the AVI as well?

Any help would be greatly appreciated.

Brigg Thorp
Software Engineer
Timex Corporation

Re: Display Transparent AVI

Daniel Strigl10-Oct-02 20:17

Daniel Strigl

10-Oct-02 20:17

Have you added the ACS_TRANSPARENT (2) flag value in the windows style value of the video window?

ACS_TRANSPARENT:
Allows you to match an animation's background color to that of the underlying window, creating a "transparent" background. The control will send a WM_CTLCOLORSTATIC message to its parent. Use SetBkColor to set the background color for the device context to an appropriate value. The control interprets the upper-left pixel of the first frame as the animation's default background color. It will remap all pixels with that color to the value you supplied in response to WM_CTLCOLORSTATIC.

Daniel Wink | ;)

---------------------------
Never change a running system!

::CreateFileMapping

Abin10-Oct-02 5:35

Abin

10-Oct-02 5:35

HANDLE CreateFileMapping(
  HANDLE hFile,                       // handle to file
  LPSECURITY_ATTRIBUTES lpAttributes, // security
  DWORD flProtect,                    // protection
  DWORD dwMaximumSizeHigh,            // high-order DWORD of size
  DWORD dwMaximumSizeLow,             // low-order DWORD of size
  LPCTSTR lpName                      // object name
);

That's the function prototype shown on MSDN, I have a question about the first parameter here: it can be a handle to a disk file if the handle value is not INVALID_HANDLE_VALUE, or else it will be using system page file. I wonder which should I choose, specify a disk file or just use the system page file, which one is better and why? Thanks.

Re: ::CreateFileMapping

Daniel Turini10-Oct-02 5:34

Daniel Turini

10-Oct-02 5:34

What are you trying to accomplish? IPC or only reading some pages of large file?

My latest articles:
XOR tricks for RAID data protection
Win32 process suspend/resume tool

Re: ::CreateFileMapping

Abin10-Oct-02 5:47

Abin

10-Oct-02 5:47

IPC. I'm trying to develop a project that requires a number of processes cooperate together, each of which needs to know exactly what other processes are doing in order to interact properly.

I'm thinking of using file mapping as my IPC approach, I'm not sure if this is a good way, though. Your help is very much appreciated.

Re: ::CreateFileMapping

Daniel Turini10-Oct-02 5:55

Daniel Turini

10-Oct-02 5:55

I would use the pagefile, because often users put it on a separate disk. I'm not a memory mapping guru, but I can see no other advantage/difference in your case.

My latest articles:
XOR tricks for RAID data protection
Win32 process suspend/resume tool

Re: ::CreateFileMapping

Paul M Watt10-Oct-02 6:21

Paul M Watt

10-Oct-02 6:21

File Mapping is a very good technique for IPC, in fact that is how COM implements its underlying IPC for local processes.

Using the system page sounds like a good way to go, then there is no file clean up afterwards. Other than that I do not think that it matters which way you do that.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: ::CreateFileMapping

Abin10-Oct-02 7:29

Abin

10-Oct-02 7:29

Thanks for you and anyone who replied. OK I still have a question here, it may sound stupid but anyway:

Is there any possibility that the mapped file will be trespassed by other process? I mean, if I have process A and B are using the mapped file(I will generate a GUID as mapping file name), is it possible, even very very slightly possible, that any contents within the mapping can be modified by processes other than A and B?

Because I need the contents to be absolutely private and secure to process A and B, this is crucial for me, otherwise I might get fired Poke tongue | ;-P

. So before I begin it I'd like to make sure. Thanks again.

Re: ::CreateFileMapping

Joe Woodbury10-Oct-02 7:42

Joe Woodbury

10-Oct-02 7:42

Bin wrote:
Is there any possibility that the mapped file will be trespassed by other process?

Yes. If you use a named object, a process with the proper security can access that object. Will it? Very unlikely, but still possible.

(Think about it, if process B can see an object owned by process A, so can process C. More importantly, your bosses need to understand that if a process has administrative rights in windows, you simply cannot make the system secure. This is akin to the adage that a physically accessable computer is not fully secure.)

Where did the crash happen?

User 665810-Oct-02 5:27

User 6658

10-Oct-02 5:27

Hi
there are some programs like MS MediaPlayer and InterVideo WinDVD which, in case of a crash, show a MessageBox with the line, the sourcefile, and a piece of the code that caused the crash. It looks like this e.g:

Unhandled exception in
"C:\Program Files\foo\main.cpp" in line: 289
ASSERT(pFoo != NULL);

How can I implement this feature into my applications?

regards
Greg

modified 12-Sep-18 21:01pm.

Re: Where did the crash happen?

Daniel Turini10-Oct-02 5:30

Daniel Turini

10-Oct-02 5:30

use this in your code:

ASSERT(pFoo != NULL);

And deliver a debug build version.

My latest articles:
XOR tricks for RAID data protection
Win32 process suspend/resume tool

Re: Where did the crash happen?

User 665810-Oct-02 5:59

User 6658

10-Oct-02 5:59

Well, I don't think Microsoft and Intervideo deliver debug versions of their programs tp the customers Confused | :confused:

There must be another way.
Furthermore the assertion dialog (or MessageBox) doesn't look the same like in the MediaPlayer or WinDVD.

modified 12-Sep-18 21:01pm.

Re: Where did the crash happen?

Daniel Turini10-Oct-02 6:03

Daniel Turini

10-Oct-02 6:03

Gregor S. wrote:
Well, I don't think Microsoft and Intervideo deliver debug versions of their programs tp the customers

Well, an ASSERT is suposed to only be present on debug Builds, right?

You can achieve the same by #define _DEBUG on your release build, or creating a proprietary fancy ASSERT macro.

My latest articles:
XOR tricks for RAID data protection
Win32 process suspend/resume tool

Re: Where did the crash happen?

Paul M Watt10-Oct-02 6:42

Paul M Watt

10-Oct-02 6:42

While in Debug mode you could use _CrtDbgReport, however that function only exists in the debug version of the C-Runtime libraries. Look at how ATLs ATLASSERT macro works.

#define _ASSERTE(expr) \
do { if (!(expr) && \
(1 == _CrtDbgReport(_CRT_ASSERT, __FILE__, __LINE__, NULL, #expr))) \
_CrtDbgBreak(); } while (0)

For release mode you could simply create your own function that reports the data in a message box, and you would use these preprocessor defines to get the line number and file: __FILE__, __LINE__

Good Luck

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: Where did the crash happen?

User 665810-Oct-02 6:50

User 6658

10-Oct-02 6:50

I finally managed to create my own macro, could you please take a look whether it is correct? Is seems to work however Wink | ;)

void _assert_(void *exp)
{
        char err[1024];
        sprintf(err, "Assertion Failed!\n\n\"%s\" in line %i.\nASSERT(%s)", \
                     __FILE__,										\
                      __LINE__,										\
                      exp);											\

        if(exp)
        {
                MessageBox(NULL, err,"Fatal Error", MB_OK|MB_ICONSTOP);
                PostQuitMessage(0);
        }
}

#define _ASSERT_(exp) { _assert_(#exp); }

For testing purposes:

void *pFoo = NULL;
_ASSERT_(pFoo != NULL);

thanks

btw why don't the pre-tags recognise tabs (\t) when I copy and paste my code?

modified 12-Sep-18 21:01pm.

Re: Where did the crash happen?

Paul M Watt10-Oct-02 7:46

Paul M Watt

10-Oct-02 7:46

Your macro looks good to me Smile | :)

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

It has been a privilege...

Georg Haan10-Oct-02 5:19

Georg Haan

10-Oct-02 5:19

...that's bugging me...
I wrote a message about a CreateProcessAsUser problem a few hours ago titled "Is it a bird? ... No It's Superuser!".

I've managed to narrow the problem, so it should be more easy to anwser...

Given that I know the name of my administrator account and it's password, how can I get SeAssignPrimaryTokenPrivilege, operating from a regular account, in order to succesfully place a call to CreateProcessAsUser?

The idea is to copy the functionality of Linux' su...

Regards,
Georg Haan(.NL)

Re: It has been a privilege...

Daniel Turini10-Oct-02 5:20

Daniel Turini

10-Oct-02 5:20

I think people at Cygwin had the same problem:

http://sources.redhat.com/ml/cygwin/2000-08/msg00445.html[^]

My latest articles:
XOR tricks for RAID data protection
Win32 process suspend/resume tool

write vertical text using GDI+

Anonymous10-Oct-02 4:33

Anonymous

10-Oct-02 4:33

I use the following two line of codes to write vertical text, it works, but the text is facing the left, reads from the top to the bottom. What shall I do if I like to have the vertical text to face the right, and read from bottom up?

stringFormat.SetFormatFlags(StringFormatFlagsDirectionVertical);
graphics->DrawString(string, -1, &myFont, origin, &stringFormat, &blackBrush);

Thanks.

Re: write vertical text using GDI+

l a u r e n10-Oct-02 4:41

l a u r e n

10-Oct-02 4:41

if there isnt a flag to set what u want (and i havent done so much text output stuff for a while) u could draw to a memdc and invert / flip it before displaying it

"... and so i said to him ... if it don't dance (or code) and you can't eat it either f**k it or throw it away"
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