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I've got a question that I would love some feedback on.
I've written a C++ CGI application running on Win2k that generates thumbnail pictures. The generation process works fine but if I have too many thumbnails to generate, my web server kills the process after 6 or 7 minutes.
What I would like to do is to have my CGI program start a seperate process that does the conversion, sends a "working" page to the brouser, and then quit. The seperate process would continue to work on the thumbnails. It would update a text file to show it's progress.
I want to avoid having more then one executable but I can't just call my CGI program again using an execl() because my program does not have an .EXE extension. It has a .CGI extension. Is there a way to start a new thread (is fork the correct wording?) from a function or in creating a new object?
Thanks for any help you can give.
- Dave S
====
Dave S
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Dave_Schneider wrote:
my web server kills the process after 6 or 7 minutes.
yes it will, the webserver does not want to keep a connection open for any longer.
MSN Messenger.
prakashnadar@msn.com
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First off, the CreateProcess() api doesn't require any special extensions (exe/com/dll/etc....) to load and exec a process.
Secondly, what could you be doing that would require a 6-7 minute response time???? Generating thumbnails should be a pretty quick operation (on the order of 100-300ms), not 7 minutes.
onwards and upwards...
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Thanks for the responses. I'm new to the whole multi-process/multi-thread thing.
So I can start another instances of my program by calling CreateProcess(), and then quit the original process without affecting my new process?
The reason it takes longer then 6-7 minutes to get a response is I am generating more then one thumbnail. My program takes a directory of pictures and looks to see if there are thumbnails for each one. If no thumbnails are found, it generates them. My problem comes when a new directory has several hundred pictures.
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Are you creating a bitmap for each thumbnail or simply copying the thumbnails onto one large image? Also, what method are you using to generate the thumbnails?
If you call CreateProcess and do not specify an owning process, then that process is independent.
FYI: CGI programs are typically not very scalable. You should use ISAPI or a C++ app server like this one [^].
onwards and upwards...
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I'm taking JPEG's of sizes ranging from 200kb-400kb (1280x960) and doing a down-sample on them to 2kb-4kb (200x150) JPEG's. I'm using the DevIL image library to do the work.
Because I want to get as much detail as I can in these thumbnails, I an using a slower down-sampler.
I'm interested in looking more at your suggestion of using a ISAPI or a C++ app server, but your link did not seem to work.
Thanks.
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Sorry, here is the right one: ^]
onwards and upwards...
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Hello, I've encountered the following error:
Warning: calling DestroyWindow in CDialog::~CDialog --
OnDestroy or PostNcDestroy in derived class will not be called.
This happens, when I unload a DLL file from my program. If I override PostNcDestroy or DestroyWindow (I should free memory there) the 2 functions never get called. The dll has a dialog interface in it, and I should clean-up the memory since the dialog is no-modal, and there is dynamically allocated memory also for strings which I display in ListView. All should work fine, but PostNcDestroy and/or Destroy Window never get called. All I get is the above metioned warning in debug mode. And because of not getting these messages, I'cant free the memory and I get memory leaks. Anyone had the same problem?
Thanks in advance,
D.
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make sure your functions are declared as virtual!
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Yes, they are declared as virtual 
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[Edited]
When your modeless dialog closes, it should do this:
DestroyWindow();
delete this;
/ravi
My new year's resolution: 2048 x 1536
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ravib@ravib.com
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Thanks for the comment Ravi,
I know that I have to call DestroyWindow() and delete this in my modeless dialog, but the problem is that I don'get notified about it, I get the warning, and my handlers are not called, the modeless dialog is contained within a DLL file, and when it's unloaded, the warning is displayed in the debugger, the handlers are not called, and I get the memory leaks.
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Ah. Perhaps you could destruct the dialog (in an orderly manner by calling a public method that cleans up properly) when your DLL unloads? Your DLL will get notified when it's about to be unloaded.
/ravi
My new year's resolution: 2048 x 1536
Home | Articles | Freeware | Music
ravib@ravib.com
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Over ride the OnCancel, OnOk event and call destroywindow and dont call the baseclass implementation.
If you calling EndDialog any where remove them and replace it with destroywindow.
MSN Messenger.
prakashnadar@msn.com
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Thank you all for the help, I'm going to try these methods, and if they don't fix that bug, I will post again 
Thanks for your attention and time
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Dear All,
I would like to create some public variables reading from my data base records. How can I do that? it's mean that there are some string stored in database. When the application initalisation. some (datatype) variables should be created as public use.
Regards,
Anson Tong
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I dont think that is possible under c/c++ i.e dynamically creating public variables...
Well you can have a list and add all the values to the list... each index humm, can be called as the dynamically created variable but its not. The variable type of each index will be same.
MSN Messenger.
prakashnadar@msn.com
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Can anyone tell me the preferred way of calling a Web Service from unmanaged C++. I don't want to use Managed code if I don't have to.
I've looked at the MS Soap Toolkit v3 and it looks like it will work, but its being deprecated later this year. Does that matter? What does anyone else use?
Ta,
Dave.
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I usually use ATL Server library[^] (I know, the name is very bad) for that purpose. Also, you can look at some 3rd party solution, such as gSoap[^].
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Thanks.
The ATL stuff looks cool - I'll give it a try.
I tried adding a web reference into a unmanaged C++ app and Visual Studio gave me loads of "Internal Error" messages boxes and seemed to break my project. Have you ever seen that one?
I'm trying to access an Apache Axis (Java) web service btw.
Ta,
Dave.
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Hi,
I have a code as below:
Class x: public CFormView
{
public:
virtual void OnInitialUpdate();
}
Class y: Public X
{
public:
Virtual void OnInitialUpdate();
}
Class z: class y
{
public:
void OnInitialUpdate();
}
When I call OnInitialUpdate () for class z it throws an exception at CFormView::OnInitialUpdate() of Class x. Could any one please help me?
Regards
Neha
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OnInitialUpdate is not called by you i suppose. It is called automatically when you create the Formview using create.
MSN Messenger.
prakashnadar@msn.com
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Dear Sir
i got start working with VC++and Using Philips API to develope speech Application.
Philips API includes callback structures like
PSPDICTCBSTRUCT
Now this same Callback structure works f9 in win32 application as in HelloWorld application.
But when i re-write same code in Buttons's click event in MFC ApplicationWizard(exe) Application
i got error as
" cannot convert from '' to 'void (__cdecl *)(unsigned long,unsigned long,long)' "
on following line to initialize callback function as
PSPDICTCBSTRUCT cbDict= {0,0, OnDictationResult,0,0,0,0};
where decleration on OnDictationResult function is
OnDictationResult(PSPDICTRCGHANDLE i_handle, PSPDICTRESULTHANDLE i_result, PSPUSERDATA i_userData)
Now let me know is their any setting in VC IDE are required to get callbacl function done in MFC ApplicationWizard(exe) type applications
Waiting for responce
Thanks in advance for all
regards
kashif gul kazi
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Call back functions of a class method need to be static.
MSN Messenger.
prakashnadar@msn.com
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