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Nope,
the compiler treats
MyClass my2 = MyClass(3,2);
as it was
MyClass my2(3,2);
(I've messed up both copy constructor and assignment operator to detect it)
and IMHO skipping the temporary object construction and the assignment operator is really weird, but I don't know what the C++ standard requires.
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.
[my articles]
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CPallini wrote: What do you think?
Well, I immediately quibbled your tests, so I did some of my own...
class MyClass
{
public:
int _a, _b;
MyClass()
{
TRACE0("Blank Constructor\n");
}
~MyClass()
{
TRACE0("Destructor\n");
}
MyClass(int a, int b):_a(a), _b(b)
{
TRACE2("Parameter Constructor(%i,%i)\n", a,b);
}
MyClass(const MyClass & proto)
{
_a = 0;
_b = 0;
TRACE0("Copy Constructor\n");
}
MyClass & operator = (const MyClass & proto)
{
_a = proto._b;
_b = proto._a;
TRACE0("Copying\n");
return *this;
}
};
void main()
{
MyClass my1(3,2);
MyClass my2=MyClass(30,20);
}
And I got:
Parameter Constructor(3,2)
Parameter Constructor(30,20)
which came as a suprise. So, the second case is being "Optimised" - even with no compiler optimisation. So C++ is treating the two cases as grammatically equivalent.
This is why I help here - I learn something by code-spelunking too!
Iain.
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Now you have to fix all that database and network stuff!
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.
[my articles]
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Is there a Windows API or a method which can convert FILE* to HANDLE of a file or convert HANDLE to FILE* ???
The background of application :I want to monitor the I/O of a special file by hooking WriteFile and the file be opened by 'fopen'.In addition, I can`t modify the function form 'fopen' to 'CreateFile'. Therefore I can`t know which handle of file should be monitored according to the first parameter of WriteFile.So I hope there is a way that can convert HANDLE or FILE* to another.
If you know it ,please tell me .
Thank you.
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I made a line
FILE *p = fopen ("foo", "rw");
and kept debugging into functions until I found the C runtime using an array of information called _osfhnd which stored the mapping between stream opened by _tsopen and HANDLE. This stream is the _file member of FILE.
_get_osfhandle
http://msdn2.microsoft.com/en-us/library/ks2530z6.aspx[^]
The below code omits any error checking whatsoever....
HANDLE FileToHandle (FILE *f)
{
return (HANDLE)(f->_file);
}
There are lots of reasons to be careful - if you're not in control of the FILE *, what's to stop them closing it without you knowing, etc.
Enjoy!
Iain.
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Dear Iain,
Thank you. Your ideal is right.
But there is a mistake in your demo code. Perhaps, you lose a function call. I believe your original thought is following:
<br />
HANDLE FileToHandle (FILE *f)<br />
{<br />
return (HANDLE)(_get_osfhandle(f->_file));<br />
}<br />
I have tried the method and verified it is right.
Enjoy!
June
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Dear Iain,
Now I encounter another problem that is how to get file`s name by HANDLE of a file. Do you know it???
If you know it, please help me.
Thank you.
Enjoy!
June.
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Thanks for using the code I *should* have written to get the HANDLE.
I suspect the filename will be stored in FILE * in a similar fashion.
If you do the same thing I did, and step into the fopen code, you can find out the information too.
Good luck,
Iain.
Iain Clarke appearing by Special Request of CPallini.
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Thank your help.
Best wish for you.
June
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i have a dialog which contains an editbox (dialog1)and whatever data i enter into the editbox is passed to another editbox.(dialog2). now if i enter any value in dialog2 the value should stay in the dialog2 editbox. but that is not happening. the value of dialog1 editbox is appearing. so how do i save this value which i entered in dialog2 editbox?
do i need to do some checks for this?
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What do you mean with save,when you want to start program again you need to these values?
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true. but that is when u restart the application. save means what ever values that is put in the editbox(dialog2) should appear than the original value(dialog 1)
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Ok for this problem you can use of Registry for save values or use of ini files.
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is there any other way out to store this value in a variable and retrieve this?
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No you want to close your program and open it again,you need to hard for save values not memory.
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Hamid. wrote: No you want to close your program and open it again
Well, but that's not what he wants to do (as far as I understood).
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But he want to uses of these values next time that he will be using of his program.
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You are missing out a lot of information.
What does "get passed" mean?
Is dialog2 the main dialog, and dialog1 is a modal dialog created in a OnSomeButtonPressed call?
Any answer to your question needs to know more about your appilcation. This doesn't sounds like a problem with edit boxes.
Iain.
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let me make it simpler...
i have a splitter control where there are lot of menu items. when i open my application a dialog(dialog1) appears where we have to provide some information. as i told u the edit box is in this dialog.
the value which is entered in the editbox is passed to another editbox in another form(take this as dialog2). that is done. i am able to do this.
now my requirement is when i enter a value in dialog2's editbox it has to get saved in a variable. and if i go to some other sceen and come back to the dialog2 screen the value which i entered should be displayed than the value in the dialog1 editbox. i am not able to do that now. want to know how can i do that.
I hope its clear for everybody.
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If I understand your description, I don't understand where the difficult part is.
What's stopping you from storing the edit text in a CString variable when dialog1 closes? You can send / post a message to dialog2 saying "Hey, reload that edit box with the CString variable!".
Just store the CString in your CDocument and pass a pointer to it to dialog1, 2, 3 or 17.
And if the dialogX's are CFormViews, it's even easier. Just use CDocument::UpdateAllViews.
Good luck,
Iain.
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the difficulty is the original value is displaying all the time. tried ur method. but its not working. i am getting the same value as of dialog1 value.
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OK, I give up.
If the original value is displaying all the time, then that means the dialog isn't closing?
If you're wanting to save the value between times when your program is running, then you've had your answeres.
In your other reply to my last post, you asked "is this the way to do it?". You can answer that for yourself, by trying it. As I no longer know what you want, and you keep changing your question every time you get a reply, then I can't answer.
Good luck,
Iain.
Iain Clarke appearing by Special Request of CPallini.
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i have done something like this
the inital value is
<br />
m_editvalue = pApp1->m_number;<br />
this will send the value from the first dialog to the dialog where there i want the value to be passed(dialog2)
now as per u have told me.
i have made a CString variable
<br />
CString str;<br />
str.Format("%d",m_editvalue);<br />
int value1 = atoi(str);<br />
<br />
now str contains the new value or the value that is there in the editbox of dialog2.
now i have passed this value to the app.
i have made a int variable in app.
<br />
<br />
int appvalue = dialog2.value1; <br />
and i have passed the value back to the dialog2. is this what needs to be done?
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Dear Friends,
I am getting problem in Creating class for Table in Oracle DB. Following steps i have follwed..
1) Created A DSN name in Control pannel- Adminstrative Tool-Data Sources
2) new class, Name it as AA and Base class as CRecordSet - OK
3)In DB Options, ODBC-- DSN Name, Snapshot -- OK
4) Put the password -- ok
5) Here list of tables should be displayed but i cant see any table.. some names are coming but they do not contain the tables which i m searching for..
Can u plz help me out to solve this problem??
Plz ask me if u want any more info..
Megha
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megha_gharote wrote: Can u plz help me out to solve this problem??
When you created the DSN, did it show the available table names?
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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