|
Is there a good way to tell whether some process has a given file open.
I am writing an application that allows the user to open a file in an arbitrary external editor. I start the editor in a spawned process with P_NOWAIT or P_DETACH flags, and want to figure out whether the editor has closed the file. Since the user can arbitrarily choose the editor, I can't make any assumptions about DDE or similar calls to the editor to query the status of the file.
The user may close the file in the editor without closing the editor, so I can't simply check whether the given PID has exited.
Thus, my question is: given a PID (process id) and a filename (full path), is there a Win32 API method of determining whether the process PID currently has the given file open?
Thanks,
Jonathan
Why couldn't Science, in the long run, serve
As well as one's uncleared lunch-table or
Mme X en Culottes de Matador? James Merrill
|
|
|
|
|
You can test if a file is open by trying to open it for exclusive access with no sharing. It the file exists but the open fails, another process has opened it.
/ravi
Let's put "civil" back in "civilization"
http://www.ravib.com
ravib@ravib.com
|
|
|
|
|
Cool! Elegant solution. Thanks.
|
|
|
|
|
I have a small but annoying problem I'm hoping someone here can help me with. I've built a small shell context menu extension dll. When my item is invoked from the menu, I create my dialog box with progress bars , set up the list of files and send them off to the dialog, which then processes them. The wierd behaviour starts when I have two shell windows ( My Computer windows ), and I run some files from each window at the same time. The underlying process is built so that the second dialog will sit waiting, ready to go, while the first one finishes - that part is ok. What is strange is that as the dialog in the first window is processing, and updating it's progress bars, the progress bars in the other dialog are also being updated.
Any clues? Thanks in advance for any help.
|
|
|
|
|
Using VC++ 6.0 and MFC
I am dynamically creating child windows in a derivative of CScrollView. This is working really well.
How can I save the child window which has the focus when another application is activated so that this can be restored when the focus is returned to my application.
Example is when user switches to Explorer then back to my app using the buttons in the start bar.
I have tried a few methods but they do not seem to behave consistently. Any suggestions will be very welcome.
Sara
|
|
|
|
|
Hi,
If I draw a rectangle on a dialog using this code it draws a nice rectangle with black frame on NT but nothing on 2000, any idea ?
CRect rect;
CClientDC dc (dlg); //get our device context
dlg->GetClientRect (&rect); //get the pointer to our window
CBrush brush (RGB (192,192,192));
dc.SelectObject(&brush);
dc.Rectangle(20,30,40,70);
|
|
|
|
|
How many Dialogs and stuff do you usually have before you start putting them into DLL's? Also, do you put more than just the dialogs into DLL's? When would I consider building a class as a DLL?
- Nitron
"Those that say a task is impossible shouldn't interrupt the ones who are doing it." - Chinese Proverb
|
|
|
|
|
I think the main criteria for putting stuff in a DLL is its ability to share the content of the DLL.
or
If the data is rarely used, and your program would benefit from only loading the DLL when it is needed.
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!
|
|
|
|
|
So if my application is pretty much canned in one main class and no one else interfaces with it, forget the DLL? Except if I have some functions and classes which aren't used often, so put them away into the DLL to avoid the overhead when they are not in use...
I guess if you don't have an explicit reason for a DLL, you probably don't need one?
- Nitron
"Those that say a task is impossible shouldn't interrupt the ones who are doing it." - Chinese Proverb
|
|
|
|
|
Nitron wrote:
I guess if you don't have an explicit reason for a DLL, you probably don't need one?
Yep. I see applications that go over 2 MB in size. Alot of that is resources and images, but still your EXEs can get as large as you want.
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!
|
|
|
|
|
Cool. Thx. Well, I had enough for one week... Have a good weekend!
Oh, I'll be sure to have a ![Beer | [beer]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/beer.gif) or for you! 
- Nitron
"Those that say a task is impossible shouldn't interrupt the ones who are doing it." - Chinese Proverb
|
|
|
|
|
I just made my mainframe class inherite from another simple class ( standalone, class, does not inherite from anything else ), and I get these errors :
afx_msg void OnStandardToolBar(NMTOOLBAR* pnmh, LRESULT* plRes);
afx_msg void OnViewToolBar (NMTOOLBAR* pnmh, LRESULT* plRes);
...
ON_NOTIFY(TBN_DROPDOWN, ITB_STANDARD_TOOLBAR, OnStandardToolBar)
ON_NOTIFY(TBN_DROPDOWN, ITB_VIEW_TOOLBAR, OnViewToolBar)
...
D:\\MainFrm.cpp(287) : error C2440: 'type cast' : cannot convert from 'void (__thiscall CMainFrame::*)(struct tagNMTOOLBARA *,long *)' to 'void (__thiscall CCmdTarget::*)(struct tagNMHDR *,long *)'
Pointers to members have different representations; cannot cast between them
D:\\MainFrm.cpp(288) : error C2440: 'type cast' : cannot convert from 'void (__thiscall CMainFrame::*)(struct tagNMTOOLBARA *,long *)' to 'void (__thiscall CCmdTarget::*)(struct tagNMHDR *,long *)'
Pointers to members have different representations; cannot cast between them
I'm assuming it's name conflict somewhere ...
Any Ideas ?
Max
P.S. I hate fridays!
|
|
|
|
|
Maximilien wrote:
P.S. I hate fridays!
 Well, I like Fridays myself -- it's the start of the weekend!
But anyway, your problem is not related to name conflicts. If you look at the error, it's expecting you to pass it a function with this signature:
void (__thiscall CCmdTarget::*)(struct tagNMHDR *,long *)
And you're passing it this:
void (__thiscall CMainFrame::*)(struct tagNMTOOLBARA *,long *)
I believe that changing the first parameter to be of type NMHDR (instead of NMTOOLBAR) should take care of the problem.
Regards,
Alvaro
Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)
|
|
|
|
|
even if it actually expect to have a NMTOOLBAR ?
I assume it's safe to do :
NMTOOLBAR* pnmh = (NMTOOLBAR* ) pNBHDR;
in the handler ?
anyway, seems to be working !
Thanks, now I can go home free as a bird !
Max.
|
|
|
|
|
Maximilien wrote:
I assume it's safe to do :
NMTOOLBAR* pnmh = (NMTOOLBAR* ) pNBHDR;
Not only is it safe, it's correct.  All the WM_NOTIFY structs have a NMHDR as their first member, think of it as inheritance for C.
--Mike--
Friday's GoogleFight results: Britney Spears 2,190,000 - Erica Weichers 23 
1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm
|
|
|
|
|
How do I add Help File Functionality to my VC++ MDI application ? Please help
|
|
|
|
|
compile your help files using HTMLHelp Workshop, so that you got the *.chm ready. Then in your method to serve the help menu item, just add:
HWND hwnd = ::HtmlHelp(this->m_hWnd, szBuff, 0, HH_DISPLAY_TOPIC);
to display the help file.
remember to include the #include <htmlhelp.h>
and the library.
|
|
|
|
|
Thanks for the help but unfortunately I am getting a Linker error saying
Linking...<br />
MainFrm.obj : error LNK2001: unresolved external symbol _HtmlHelpA@16<br />
Debug/MDI2.exe : fatal error LNK1120: 1 unresolved externals<br />
Error executing link.exe.<br />
<br />
MDI2.exe - 2 error(s), 0 warning(s)
I copied the htmlhelp.h file to the VC98 include directory
and copied the htmlhtlp.lib file to th eVC98 lib directory.
Also I my .cpp I included like #include "htmlhelp.h"
What am I Doing wrong ? Please help
|
|
|
|
|
did you reference the HTMLHEML.lib file in your projects link settings? You need to actually reference the lib in your project, otherwise the linker will not know that it needs to link that file in.
Hit Alt + F7 then go to the link tab. In the "Object/Library Modules" edit field add HTMLHelp.lib and that should fix your problems.
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!
|
|
|
|
|
Thanks a lot for the suggestions . I was able to invoke a File. THanks
|
|
|
|
|
What do you recommend for creating/editing the help file text/source?
Gaulles
|
|
|
|
|
I am using HTMLHelp Workshop. You can download it from Microsoft's web site.
|
|
|
|
|
I am trying to create a thread to monitor a USB-connected ADC module. Its driver uses a callback function for the configuration of the module. It requires a CWnd handle given to it such that when it has a buffer filled, it sends a OLDA_WM_BUFFER_DONE message to the thread. I created a UIThread so that it would have a message handler and I could create my OnBufferDone function. (Which is working and tested in a single thread situation.) It needs to be in a separate thread so that I can empty the buffer quickly
and move the sample data into my internal buffers and return it back to the ADC module driver before the next buffer_full message comes in.
Does anyone know how to create or get a HWND for a UIThread so that this driver can know where to send messages to my thread?
Thanks in advance,
Dave
|
|
|
|
|
Have you had a look to PostThreadMessage[^] ?
HTH,
K.
I hurt so bad inside
I wish you could see the world through my eyes
It stays the same
I just wanna laugh again
|
|
|
|
|
Hello to all.
I've checked this following article (http://www.cuj.com/experts/1906/hyslop.htm?topic=experts) at CUJ web site and decided to use it in my own application.
So here we go. I have managed to implement the factory inside a windows DLL. But i'm having weird problems with it. Mainly the genericFactory::create method.
This is how i've implemented it (with the modification that I use a pointer to a function with three std::string parameters) :
template <class manufacturedobj,="" typename="" classidkey="">
std::auto_ptr<manufacturedobj>
genericFactory<manufacturedobj, classidkey="">::create(const classIDKey &className,
const std::string& p1,
const std::string& p2,
const std::string& p3) const
{
std::auto_ptr<manufacturedobj> ret(0);
FN_REGISTRY::const_iterator regEntry=registry.find(className);
if (regEntry != registry.end())
{
ret = regEntry->second(p1, p2, p3);
}
return ret;
}
And in my client code this is how I call it :
std::auto_ptr<mysqltable> tbl(0);
tbl = genericFactory<mysqltable>::instance().create("HistoricalDataTbl", host, user, pwd);
-----------------------------------------------------------------------------------------------
When I trace inside the create method, the "ret" variable is fine and points to a valid MySQLTable object. BUT, when the function returns to the client code... I get an unhandled exception error. This error is generated inside the auto_ptr<>::reset() method. To be more precise, the "tbl" auto_ptr in the client code is supposed to be initialized with a NULL pointer but when getting back from genericFactory::create method the "tbl" pointer points to an invalid MySQLTable object.
The quilty code inside auto_ptr :
void reset(_Tp* __px=0) {
_Tp* __pt = this->get();
if (__px != __pt)
delete __pt; //offending line...
this->__set(__px);
}
So i'm currently puzzled has to why the "tbl" variable points to a bad MySQLTable object!?!?!?!
Any help would be greatly appreciated
Luc.
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
