C / C++ / MFC

Does DeleteFile function returns immediatly?

23-Dec-14 22:57

Not fix at all, just a typing error in my CLID declaration. What error do you get ?

sdancer75

Donguy19763-Jul-13 7:00

Donguy1976

3-Jul-13 7:00

Hello there,

If i call DeleteFile on a file that's pretty large, does the function wait until the entire file is deleted before returning?

Or does it return immediately? i.e., the control is passed to OS to complete the task of deletion and then return immediately?

For e.g., if i am deleteing 5 files inside a loop and 2 of them happen to be larger size, will it wait until each file is completely deleted before going to the next one?

If it doesn't, then there's a probability that when the next file is called by DeleteFile the previous one might still be in the process of deletion and it could fail.

Is there a possibility like that?

Re: Does DeleteFile function returns immediatly?

jeron13-Jul-13 7:49

jeron1

3-Jul-13 7:49

~~From the documentation I'm guessing that it will not return immediately, accurate return codes require the operation to complete.~~ Yikes! Note to self...read the whole thing first! sorry.

modified 3-Jul-13 14:27pm.

Re: Does DeleteFile function returns immediatly?

Jochen Arndt3-Jul-13 8:12

Jochen Arndt

3-Jul-13 8:12

As far as I know, the function returns immediately and the deletion occurs in the background. This is always true if the file is still opened (see DeleteFile[^] in the MSDN):

Quote:
The DeleteFile function marks a file for deletion on close. Therefore, the file deletion does not occur until the last handle to the file is closed.

Overall, there should be no significant difference in time for large and small files because the file data itself are left unchanged on the disk. Only the directory entries are touched.

Calculator in C Language

anasshad3-Jul-13 2:11

anasshad

3-Jul-13 2:11

Hello!!! I'm learning C language and trying to make a calculator. Here's the code:

#include <stdio.h>
int main()
{
    int a, b, add, sub, mul;
    float div;
    char choice='y';
    do {
    printf("Enter any choice:\n1. Addition(a)\n2. Subtraction(b)\n3. Multiplication(c)\n4. Division(d)\n5. Exit(x)");
    scanf("%c", &choice);
    switch(choice)
    {
                  case 'a':
                       {printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       add = a + b;
                       printf("Sum: %d\n", add);
                       break;}
                  case 'b':
                       printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       sub = a - b;
                       printf("Difference: %d\n", sub);
                       break;
                  case 'c':
                       printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       mul = a * b;
                       printf("Product: %d\n", mul);
                       break;
                  case 'd':
                       printf("Enter any two numbers:");
                       scanf("%d %d",&a, &b);
                       div = a / b;
                       printf("Quotient: %f\n", div);
                       break;
                  case 'x':
                       break;
                       }
                       }while(choice!='x');

                  return 0;
                       }

The problem is that it is not looking very good. I'll be very thankful if anyone could help.

Richard MacCutchan3-Jul-13 2:42

3-Jul-13 2:42

anasshad wrote:
I'll be very thankful if anyone could help.

I would suggest spending some time looking through the beginners section articles[^] for ideas and examples.

Use the best guess

Maximilien3-Jul-13 2:45

Maximilien

3-Jul-13 2:45

Does it compile ?
Does it crash ?
Does it give wrong answer ?
Are you able to read numbers from the user ? (outside of this example?)
Have you tried debugging ?

Nihil obstat

Jonathan Davies3-Jul-13 3:03

Jonathan Davies

3-Jul-13 3:03

For a calculator the probable way to have it look would be like the keypad on a calculator, but as you're just starting that's a bit of a jump. As a first step why not try a Window or Dialog with two Edit boxes for the numbers and buttons to select +, - etc. The articles here will help with that as already mentioned.

Slider not working properly.?

David Crow3-Jul-13 4:47

David Crow

3-Jul-13 4:47

anasshad wrote:

The problem is that it is not looking very good.

Meaning what exactly? Confused | :confused:

"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

"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous

mbatra312-Jul-13 23:52

mbatra31

2-Jul-13 23:52

Hi,

I have a slider control on a dialog box. I am playing a video file and slider moves according to the video elapsed. Suppose I have set the slider range to 100. Now till some point say 90, the slider moves to the point wherever I click the mouse. but at the last point in between some range say 90 - 100 (to the end of the slider), if I click the mouse button anywhere, slider jumps to the end.

I am using a TimeLine control where user can add more than 1 video (1, 2, 4, 8, 10 , 50 etc......), If I use only one video, slider moves as per the video progression.....Issue arises when I add more than 1 video and click on the start button, slider starts moving....Now when I drag the slider to any position or I click the mouse button anywhere on the slider control, slider thumb moves to that position and immediately jumps back to some other position. This is the Issue, I am facing.

Can anybody share some sample code where slider is moving with the video showing the progress of the video.

I want to implement a functionality similar to VLC player. Wherever user clicks the mouse, slider moves to that point.

Any help will be appreciated.

Regards,
Mbatra

modified 3-Jul-13 9:15am.

Re: Slider not working properly.?

Maximilien3-Jul-13 3:01

Maximilien

3-Jul-13 3:01

Derive you own class from CSliderCtrl and handle the left button down

(I have no merit, this is from a simple google search)

C++

void MySlider::OnLButtonDown(UINT   nFlags, CPoint   point)
{
    CSliderCtrl::OnLButtonDown(nFlags, point);
    CRect rectClient, rectChannel;
    GetClientRect(rectClient);
    GetChannelRect(rectChannel);
    int nPos = (GetRangeMax() - GetRangeMin())*(point.x - rectClient.left - rectChannel.left) / (rectChannel.right - rectChannel.left);
    SetPos(nPos);
}

Nihil obstat

Re: Slider not working properly.?

mbatra313-Jul-13 3:16

mbatra31

3-Jul-13 3:16

I have done this...its working ....

Please read below:

Hi,

I have a slider control on a dialog box. I am playing a video file and slider moves according to the video elapsed. Suppose I have set the slider range to 100. Now till some point say 90, the slider moves to the point wherever I click the mouse. but at the last point in between some range say 90 - 100 (to the end of the slider), if I click the mouse button anywhere, slider jumps to the end.

I am using a TimeLine control where user can add more than 1 video (1, 2, 4, 8, 10 , 50 etc......), If I use only one video, slider moves as per the video progression.....Issue arises when I add more than 1 video and click on the start button, slider starts moving....Now when I drag the slider to any position or I click the mouse button anywhere on the slider control, slider thumb moves to that position and immediately jumps back to some other position. This is the Issue, I am facing.

Can anybody share some sample code where slider is moving with the video showing the progress of the video.

I want to implement a functionality similar to VLC player. Wherever user clicks the mouse, slider moves to that point.

Any help will be appreciated.

Regards,
Mbatra

How I get the Header HDC of listview in custom draw?

JoneLe862-Jul-13 9:04

JoneLe86

2-Jul-13 9:04

I want to customize the header of a listview, so in NM_CUSTOMDARW i have

C++

Test = (LPNMLVCCUSTOMDARW)Lp <<lparam
(Test->nmcd.hdc)

which for the listview without the header, i tried using

C++

Test = (LPNMCUSTOMDARW)Lp <<lparam

and then

C++

Test->hdr.hwndFrom

C++

if(Test->hdr.hwndFrom == listview_getheader(LIST))

but it does not work, the listview_getheader(LIST) gives the right hwnd, but how about Test->hdr.hwndFrom, it seems i missed something...

Re: How I get the Header HDC of listview in custom draw?

Richard MacCutchan2-Jul-13 20:41

Re: How I get the Header HDC of listview in custom draw?

2-Jul-13 20:41

JoneLe86 wrote:
C++
Test = (LPNMCUSTOMDARW)Lp <<lparam

What is Test and what is its value, and that of lp, after this statement?

Use the best guess

JoneLe863-Jul-13 5:41

JoneLe86

3-Jul-13 5:41

LPNMCUSTOMDARW Test = (LPNMCUSTOMDARW)lp

I was in the wrong way, Jochen Arndt explained that I should subclass the header first...

Thanks

Re: How I get the Header HDC of listview in custom draw?

Jochen Arndt2-Jul-13 21:11

Jochen Arndt

2-Jul-13 21:11

The header control is a child window of a list. If you want to customize the header, you must use owner drawing for the header itself.

When using MFC, derive a CHeaderCtrl class and implement the virtual DrawItem() handler. To connect this header control class to your list, use subclassing. To enable owner drawing of header items, set the HDF_OWNERDRAW flag for the header items.

See Deriving a Custom CHeaderCtrl in the Using the Header Control[^] article.

This example contains complete implementation code including the DrawItem() function: http://www.codeguru.com/cpp/controls/listview/sorting/article.php/c977/Indicating-sort-order-in-header-control.htm[^].

Re: How I get the Header HDC of listview in custom draw?

JoneLe863-Jul-13 5:38

JoneLe86

3-Jul-13 5:38

hmm I wonder why Everything need to be subclassed, thanks for this information it did help....

AVI Splitter Filter does not return its mediatype

sdancer752-Jul-13 8:29

Re: AVI Splitter Filter does not return its mediatype

2-Jul-13 8:29

The AviSplitter Filter's input pin, according to the MSDN is accepting the following mediatype

MEDIATYPE_Stream, <br />
MEDIASUBTYPE_Avi

While my own async filter is trying to connect with this filter in the method (located in amfilter.cpp file)

C++

HRESULT CBasePin::TryMediaTypes(IPin *pReceivePin, __in_opt const CMediaType *pmt, IEnumMediaTypes *pEnum)

at the following statement that it supposed to receive the AVISplitter input pin, mediatype,

C++

hr = pEnum->Next(1, (AM_MEDIA_TYPE**)&pMediaType,&ulMediaCount);

it retuns FALSE.

Why is that happens ?

sdancer75

Richard MacCutchan2-Jul-13 20:37

Re: AVI Splitter Filter does not return its mediatype

2-Jul-13 20:37

sdancer75 wrote:
t retuns FALSE.

Why is that happens ?

Explanation is at http://msdn.microsoft.com/en-us/library/windows/desktop/dd376602(v=vs.85).aspx[^].

Use the best guess

sdancer752-Jul-13 22:01

Re: AVI Splitter Filter does not return its mediatype

2-Jul-13 22:01

Thanks,

It seems that AVISplitter does not suggest any mediatype but my mediatype fails at

C++

hr = pReceivePin->ReceiveConnection((IPin *)this, pmt);

with error code 0x8004022f

Do you have any idea ?

Regards,

sdancer75

Richard MacCutchan2-Jul-13 22:10

Re: AVI Splitter Filter does not return its mediatype

2-Jul-13 22:10

And what does that error code tell you?

Use the best guess

sdancer752-Jul-13 23:58

Re: AVI Splitter Filter does not return its mediatype

2-Jul-13 23:58

Debugging the dshow library, the first error internal decription is

0x8004022f error code<br />
VFW_E_INVALID_FILE_FORMAT

but the same dshow method returns to the caller, the following description

VFW_E_NO_ACCEPTABLE_TYPES<br />
0x8004022f

I think that something wrong is going on with my code in my async filter.

C++

HRESULT result = m_pIo->SyncRead(llPosition, lLength, pBuffer);

It reads the first 0x18 bytes and after that, it returns the error. Other tests I did, it continues to read or parsing the avi file, but my code fails.

If its not a read error, then something wrong went with the AVI header parse or the MediaType templates declaration.

Note that the AVI is fine and is tested successfuly with other 3rd party players.

Regards,

sdancer75

sdancer753-Jul-13 2:11