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If you're using MFC, why not respond to the message the MFC way?
ON_WM_SYSCOMMAND()
void CMyVIPTestDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
if (nID == SC_CLOSE)
{
ShowWindow(SW_HIDE);
return;
}
CMyDialog::OnSysCommand(nID, lParam);
}
That works fine for me - I just tested it.
It's always curious to me how often the PreTranslateMessage() method is misused. 
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif)
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Thanks for your reply.
Acctually, I think the PreTranslateMessage is the most misusable method.
When don't know where to handle the message, the first place to place the code is the PreTranslateMessage.
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fantasy1215 wrote: When don't know where to handle the message, the first place to place the code is the PreTranslateMessage.
That's why it's a good idea to know how to use the documentation.
All the MFC message map macros for WM_ window messages start with
"ON_WM_". If the message map macro doesn't exist for a given message,
there's always ON_MESSAGE, which will handle any message.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Hi,
I was wondering if someone could clear this up for me.
Consider the below statement:
<br />
#define randomise(i) rand() % (i)<br />
The way I see this, both randomise and rand are functions.
But a search online made me think randomise could also be deemed a macro.
Is randomise, in computer science terms, a function or a macro (or both)?
Cheers,
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randomize is a macro.
rand is a function in the CRT library, but in the code you've shown,
it's just a token used during expansion of the randomize macro by the
pre-processor.
The VC/VC++ docs call your randomize macro a "function-like macro".
That's my take on it 
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://www.codeproject.com/script/Forums/Images/coffee.gif)
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Hi Mark,
Thanks for your reply.
Looking at the definition for a function:
"In computer science, a subroutine (function, method, procedure, or subprogram) is a portion of code within a larger program, which performs a specific task and can be relatively independent of the remaining code"
Could I argue that by calling randomise() it's performing a "specific task"?
The difference between a macro and a function seems to be vague.
Thanks,
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MarkBrock wrote: Could I argue that by calling randomise() it's performing a "specific task"?
Of course you could, but you'd be wrong LOL - just kidding
The thing is, you can't "call" randomize. The compiler pre=processor replaces
occurrences of randomize(n) to the token (macro expansion), so the actual code
called at runtime is rand() % (i).
Note that more parenthesis should probably be used here...
#define randomize(i) (rand() % i)
... just in case you use it in a complex expression...
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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MarkBrock wrote: The difference between a macro and a function seems to be vague.
Maybe for computer science, but not for the compiler (and developer) point of view. 
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.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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As far as the compiler is concerned, randomise() doesn't even exist.
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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Yeah I understand what you guys are saying now.
The preprocessor goes through and replaces randomise() with the defined macro before the code is compiled into a binary.
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I want to write a small service program to hook the system events such as the system is being to shutdown. I want to intercept the user's select before the OS. For example, the user select to shutdown the system, then my service intercept the message first and check if the specified job has been done or not, if not, do it, otherwise left the message to the system directly. How to resolve it?
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This is a service application, right? If so...
Starting in Vista, you can register for the SERVICE_CONTROL_PRESHUTDOWN
notification and take time to finish the job.
See HandlerEx Callback Function[^]
For XP and below, here's what the docs say about the
SERVICE_CONTROL_SHUTDOWN event:
The SERVICE_CONTROL_SHUTDOWN control code should only be
processed by services that must absolutely clean up during
shutdown, because there is a limited time (about 20 seconds)
available for service shutdown. After this time expires,
system shutdown proceeds regardless of whether service shutdown
is complete. Note that if the system is left in the shutdown
state (not restarted or powered down), the service continues
to run.
If the service requires more time to clean up, it should
send STOP_PENDING status messages, along with a wait hint,
so the service controller knows how long to wait before
reporting to the system that service shutdown is complete.
However, to prevent a service from stopping shutdown, there
is a limit to how long the service controller waits. If the
service is being shut down through the Services snap-in, the
limit is 125 seconds. If the operating system is rebooting,
the time limit is specified in the WaitToKillServiceTimeout
value of the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.freetls.fastly.net/script/Forums/Images/coffee.gif)
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Thanks for your reply. I use xp. Yes, it should be a service app. I haven't began to write it so far, but i want to. Because i always forget to do something before i start and end oneday's work.
What i really want to is that, when i select to shutdown my system, it should pop up a messagebox to query the specified task has been done or not. If i know i had completed it, i would select yes to shutdown the system, and if not, i would select no, then the system would not receive shutdown message, so i would have the chance to return the system to complete the specified task.
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If you need a user interface, a better, simpler solution
would be a GUI app with a hidden main window that responds to the
WM_QUERYENDSESSION Message[^].
I don't think you can prevent shutdown from a service...
I could be wrong 
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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you meant i could not prevent shutdown from a service or a normal app, or only service couldn't?
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Only a service.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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OK. According what you told me, I can intercept the shutdown message and prevent shutdown event, right?
If a normal app can deal with, how to do it?
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The link to the WM_QUERYENDSESSION docs I gave you has all the info.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Thanks, both.
I think i have got the real way to implement what i want now.
Regards
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Thanks from me too, David!
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Hello all,
First off, I'll just let you guys know that I'm really new at this.
I need some help with a simple C++ program using arrays and loops to create a 20 question quiz. The only thing the program needs to accomplish is allow the user to enter 20 multiple choice answers A,B,C, or D and compare the user entered answers to a correct set of answers to calculate a percentage of correct answers entered. If anyone could just point me in the right direction, or give me a quick example of what I should have, that would be greatly appreciated.
This is what I have so far.. but its not much.
#include <iostream><br />
using namespace std;<br />
<br />
int main()<br />
{<br />
const int NUM_QUESTIONS = 20;
char user_answers[NUM_QUESTIONS];
char correct_answers[NUM_QUESTIONS];<br />
int count;
int correct;<br />
char correct_answers[count] = {B, D, A, A, C, A, B, A, C, D, B, C, D, A, D, C, C, B, D, A} <br />
<br />
cout << "\t\t*******************************\t\t\n";<br />
cout << "\t\t*****Driver's License Exam*****\t\t\n";<br />
cout << "\t\t*******************************\t\t\n\n";<br />
<br />
<br />
for (count = 0; count < NUM_QUESTIONS; count++)<br />
{<br />
cout << (count + 1) << ". ";<br />
cin >> user_answers[count];<br />
}<br />
<br />
if (user_answers[count]==correct_answers[count])<br />
{<br />
correct++;<br />
}<br />
<br />
cout << endl; <br />
cout << correct;<br />
<br />
<br />
return 0;<br />
}</iostream>
Thanks
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Well it is a fairly good starting point for a newbie. Why are you stuck now?
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.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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the oso wrote: The only thing the program needs to accomplish is allow the user to enter 20 multiple choice answers A,B,C, or D and compare the user entered answers to a correct set of answers...
Isn't that what it's currently doing?
the oso wrote: ...calculate a percentage of correct answers entered.
cout << correct / NUM_QUESTIONS;
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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int count;
int correct;
char correct_answers[count] = {B, D, A, A, C, A, B, A, C, D, B, C, D, A, D, C, C, B, D, A}
This can only cause problems. correct_answers[count] should probably be correct_answers[NUM_QUESTIONS] since count is not initialized.
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