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No, it's not the best way - the best way would be to define an operator== for Student, then use the operator== defined for std::list. Also - isn't the 'name' member a std::string? In which case that has an operator==
Anyway - I'd do this:
class Student
{
public:
std::string name;
int age;
friend bool operator==(Student const& left, Student const& right)
{ return left.age==right.age && left.name==right.name; }
};
std::list<Student> _studentList1;
std::list<Student> _studentList2;
Then in code, I could do
if (_studentList1 == _studentList2)
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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Hi
I am building a out of proc COM Server, which would be registered as service. I want my server to be a singleton, so I have declared DELCARE_CLASSFACTORY_SINGLETON in my coclass. My server startup code RegisterClassObjects with REGCLS_MULTIPLEUSE flag. However, it is possible to launch 2 instances of my server process; one that is launched by the service manager and running under the system account; the second one can be launched from the current user's account.
How do I prevent mutiple instances of my COM server, irrespective of the user accounts?
Thanks in advance
Vivek Ragunathan
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You can create a global named mutex to prevent running multiple instances of an EXE across multiple use accounts.
Prefix the mutex name with "Global\"
Use CreateMutex[^] to create the object.
If calling GetLastError[^] after this returns ERROR_ALREADY_EXISTS the EXE can quit itself using PostQuitMessage[^].
«_Superman_»
I love work. It gives me something to do between weekends.
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Thanks. That is one way to solve the problem.
But what I am really looking for is a way that COM infrastructure would take care of. What this means is I should not report error to the user, instead return the reference of the already created COM object.
If the COM server is launched as service and all users connect to it using CoCreateInstance, they get the same reference. But when the COM server is launched using the current user account, things are screwed up as a second instance is created. Instead COM should not create the second instance, instead return the reference of the COM object hosted in the service.
Thanks
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The syatem scrollbar is overrided, but it shows both of system amd myself. Can I kill the system's or hide it? Help me, please! Thank you!
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Hi,guys!
I want to develop a COM control that can be used by other people.
First, i want develop a MenuBar using ATL,and then this MenuBar can be drag in other frame window.
I'm using vs 2005,how can i get this? Any tutorial articles or source code for this ?
Any help would be appreciate !
modified on Wednesday, August 12, 2009 1:48 AM
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Hi, guys, I'm writing simple tool for interest, like managing softwares, file association or IE history.
But when I get into this field, I find there are many information stored in files or registry. Like "index.dat" or "HKLM\SOFTWARE\Clients".
So I want to know, where I can get more information about such thing( registry about shell )?
Thanks in advance. 
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You could start here for information on the Windows Registry. But please take note of the warnings about changing values inside the Registry, as it is easy to get it wrong and make your system unusable. Also try searching CodeProject and Google.
modified on Tuesday, September 8, 2009 5:58 PM
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Thank you very much.
I'm one developer.
I try to MSDN/Google/CodeProject etc, when I encounter problems.
But I want one way to know what registry keys and values mean, such as how to set default browsers, how to change advanced UI of windows etc.
So I can solve problems more professional.
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SpringLion wrote: I want one way to know what registry keys and values mean
Your question is beyond the scope of these forums. There are hundreds of registry keys and values but no standard work of reference to describe them all. Try this site for a start, and then when you have a single question about a specific registry key, come back here and post your question.
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how to find Textbox value in the DirectUI
I did not find the use of API GetWindowText
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DirectUI is completely undocumented, all you can hope for is that someone has reverse-engineered how that control works and posted about it on the net.
--Mike--
Dunder-Mifflin, this is Pam.
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I have legacy code written under VC6 which use a lot of auto_ptr. And, have problem to build it under VS2008/VC9, becouse it's put auto_ptr in vector, that isn't accepted in VC9. Then, I want share_ptr to replace it. Can I just replace them at where they are declared?
Thanks,
Hawk
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hawkgao0129 wrote: I want share_ptr to replace it. Can I just replace them at where they are declared?
Yes.
The difference between auto_ptr and shared_ptr is that auto_ptr passes ownership around like a token, and it's possible for ownership to expire (and the object to be deleted) before you expect.
shared_ptr is like lots of people holding a plate - the plate doesn't break until everyone's let go of it.
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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In legacy code, it employed auto_ptr::release() to free resource. When i use shared_ptr, how to release resource? use "delete" keyword to call destructor of shared_ptr?
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No - use the reset()[^] method.
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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you mean shared_ptr::reset(0)? Why tr1::shared_ptr doesn't have an explicit release() function? Do auto_ptr::reset(0) and auto_ptr::release() have the same mean?
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Oh, shared_ptr::reset() can be called without argument. That means set it become empty. Maybe equal to auto_ptr::release()
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hawkgao0129 wrote: Maybe equal to auto_ptr::release()
For your purposes, yes - they're equivalent
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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I have been wondering what the logic was behind the fact that the ifstream read method sets the eofbit as well as the failbit on a read failure, but can find no explanation. I can see that if you are just checking for EOF in a loop then setting the eofbit will stop any future reading, but this also hides the cause of the error. That is if we have not actually reached the end of the file, then there is nothing to tell us this fact. If you try to read a 25k file and the codecvt do_in method returns error after reading only half a line of text, then both bits are set and there is nothing to tell us that we have not just read the entire file. I can easily hack my way around the problem, but the fact that I would have to do that is ridiculous.
Does anyone have an idea or explanation for this behavior?
INTP
"Program testing can be used to show the presence of bugs, but never to show their absence."Edsger Dijkstra
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Looking at the C++ standard specification for read (27.6.1.3 paragraph 28):
Characters are extracted and stored until either of the following occurs:
—n characters are stored;
—end-of-file occurs on the input sequence (in which case the function calls setstate(failbit|eofbit), which may throw ios_base::failure(27.4.4.3)).
There are two outcomes - either we can read n characters or not. If not, failbit and eofbit get set.
BTW - the idiomatic way (from what I'veseen) to loop on a stream isn't to check for eof, it's to check the stream status like so:
std::ifstream f(...);
while(f)
{
}
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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Here is that basic problem, the while loop works great but the test calls an over-ride that is just checking if the EOF has been reached (overloaded … etc.). Which makes since accept when that is not true? If an error occurs while reading, you need to know that is what happened; just saying that you have reached the EOF, when untrue, gives the wrong information. An error has occurred, true, but it is not because you reached the end of the file (EOF). This little piece of information is very important. One work around, which applies to C as well, is to get the size of the file before reading it; is to compare the number of bytes read as opposed to the size of the file. The main difference between C and C++ (I may be wrong) is that a read error can occur without reaching the EOF, so you need to check for both while reading a file. I will grant that if you try to read past the EOF that it is an error and you have reached the EOF. But before reaching the EOF, only an error flag should be set; indicating that a read occurred. If it sets the failbit and the eofbit every time an error occurs, it is self defeating and is lying to the developer
INTP
"Program testing can be used to show the presence of bugs, but never to show their absence."Edsger Dijkstra
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[edit]Pressed 'Post Message' with no message - DOH![/edit]
If the failbit is set, you know reading terminated because of an error. eofbit set alone is an indicator of end-of-file. Sounds like you just need to change the priority of checks round a bit?
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