C / C++ / MFC Discussion Boards

Re: Who calls main()

Richard MacCutchan14-May-11 2:58

Richard MacCutchan

14-May-11 2:58

Luc Pattyn wrote:
The entry point's name may vary, in C it normally is called main, and sometimes WinMain.

Not quite; these are the start points for the user part of the application, and are called by the initialisation routine, which is why (Win)main() has to have a specific signature. The actual entry point of the exe is much earlier and is part of the framework library that is automatically added by the linker.

The best things in life are not things.

Re: Who calls main()

Luc Pattyn14-May-11 3:12

Luc Pattyn

14-May-11 3:12

You're quite right.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.

Re: Who calls main()

bob1697214-May-11 3:21

bob16972

14-May-11 3:21

The book "Linkers & Loaders" by John R. Levine is a good resource for questions involving this and similar subject matter.

Basic C++ String Question

AmbiguousName13-May-11 19:45

AmbiguousName

13-May-11 19:45

hello guys... I have this piece of code. Lets say my name contains 'u' one time, my code will reduce the string size by 1, exludes the 'u' from string and displays it on screen.

if (chr[i] == 'u'){
       count++;
}
else{
       cout<<chr[i];
}
cout<<"\nIt has "<<strlen(chr) - count<<" characters.";

Now I am using if - else here...can these two tasks be done in just if ? Like incrementing count and displaying name in if without using else.

Re: Basic C++ String Question

Graham Breach13-May-11 20:49

Graham Breach

13-May-11 20:49

Yes:

if(chr[i] != 'u' || !++count) {
  cout << chr[i];
}

Whether you should do this or not is another question - it's a lot harder to understand.

Re: Basic C++ String Question

Stefan_Lang16-May-11 3:15

Stefan_Lang

16-May-11 3:15

Ummmm, definitely not advisable:

1. Whether this works or not is compiler dependend - a compiler is free to evaluate the left or right side of an || operator in whatever order it likes!

2. Like you said, hardly anyone will understand, and even those that do will doubt what it does was actially intended, and might decide to 'fix' it wrongly.

Apart from that - interesting thought; I was about to answer 'no' Wink | ;)

Re: Basic C++ String Question

Craig Longman18-May-11 5:56

Craig Longman

18-May-11 5:56

Stefan63 wrote:
1. Whether this works or not is compiler dependend - a compiler is free to evaluate the left or right side of an || operator in whatever order it likes!

Erm... hold on a sec here... Short-circuiting IS mandated, and can only work if it's evaluated in order. It's always true for PODs.

The only caveat is, if it is a class, and that class has an overloaded && or || operator. Then, both sides will be evaluated, so that the compiler can pass the element on the right hand side as a parameter.

One (very) good reason to never, ever overload them.

At least, this is the way I understand it, and I can't imagine anything undoing that, as tons of code that did this:

if( pszString != NULL && *pszString != '\0' )

would randomly crash if *pszString was evaluated first. Course, in this example the actual comparisons can be removed, but I was trying to be explicit.

N'est pas?

-- CraigL

Re: Basic C++ String Question

Stefan_Lang18-May-11 6:05

Stefan_Lang

18-May-11 6:05

I've learned not to rely on evaluation order, but I just looked it up and found my argument would only be true in cases where both argument sneed to be evaluated in any case, such as in an addition. In fact, Stroustrup explicitely names the exception, and that exception is exactly what you said:

"The operators ' (comma), && (logical and), and || (logical or) guarantee that their left-hand operand is evaluated before their right-hand operand."
(Bjarne Stroustrup, The C++ Programming Language, Third edition, page 123)

So I stand corrected.

Thanks for pointing this out.

Re: Basic C++ String Question

Stefan_Lang16-May-11 3:30

Stefan_Lang

16-May-11 3:30

I think there's some piece of information missing: Your code doesn't show a loop, or any other construct that loops through the characters in chr, and there's no point in displaying count before the end of that loop. Then in your request you suggest displaying 'name' within your if block, but there's no variable name, and if this should refer to chr, there is no point in displaying it fully for every value of i that you use in that if statement.

Unless your string chr will always be exactly "u" (i. e. a string of 1 character, which is 'u'), your question, taken literally, doesn't make much sense.

Besides, why do you want to get rid of that else statement?

How create a GUI to allow screen capture?

Member 296547113-May-11 11:29

Member 2965471

13-May-11 11:29

How create a GUI to allow screen capture?

Re: How create a GUI to allow screen capture?

Albert Holguin13-May-11 11:48

Albert Holguin

13-May-11 11:48

You mean other than the built in windows one? Do you only want a subset of your screen captured?

Re: How create a GUI to allow screen capture?

Member 296547113-May-11 12:06

Member 2965471

13-May-11 12:06

I want to implement a mechanism that allows users to easy select the capture area (the entire screen, the window of a program, a rectangle, ...)...is it possible?

Re: How create a GUI to allow screen capture?

Mark Salsbery13-May-11 12:57

Mark Salsbery

13-May-11 12:57

Yes it's possible.

Which part are you not sure about?

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: How create a GUI to allow screen capture?

Member 296547113-May-11 13:43

Member 2965471

13-May-11 13:43

I want to realize a GUI like this:

With mouse pointer I'd want:
Entire Screen Capture
Program Window Capture
Part of a Program Window
Select Generic Rectangle

but I don't know which API I've to use in order to do this. May you help me please?

Re: How create a GUI to allow screen capture?

Amarnath S13-May-11 17:00

Amarnath S

13-May-11 17:00

This is possible. One of the early editions of Petzold's Windows books - "Programming Windows 95" gives an example of the BitBlt() which does exactly this. This is done in raw Windows API. You can, of course, redo it in C# or your favorite language.

Re: How create a GUI to allow screen capture?

Member 296547114-May-11 2:55

Member 2965471

14-May-11 2:55

yes, i know BitBlt(), but how can i get the handle of the window that mouse over?how can i select, with mouse, a rectangle of the screen?

Re: How create a GUI to allow screen capture? [modified]

Mark Salsbery14-May-11 6:34

Mark Salsbery

14-May-11 6:34

Member 2965471 wrote:
but how can i get the handle of the window that mouse over?how can i select, with mouse, a rectangle of the screen?

This is relatively simple if you know anything about Win32 UI/graphics programming. Since you seem to want to skip that part, why not just search for examples?

Binging "win32 draw selection rectangle on desktop" finds many examples, including this...

Screen Capture (Simple Win32 Dialog Based)[^]

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

modified on Saturday, May 14, 2011 12:44 PM

red squiggly line - misspelt words

si_6913-May-11 5:42

si_69

13-May-11 5:42

Hi
Does anyone know how to get/use the red squiggly line used in Ms word for spelling mistakes

thanks

simon

Re: red squiggly line - misspelt words

Albert Holguin13-May-11 7:22

Albert Holguin

13-May-11 7:22

This is not the proper forum for this question... this is "Forum: C / C++ / MFC"

Re: red squiggly line - misspelt words

Hans Dietrich13-May-11 13:09

Hans Dietrich

13-May-11 13:09

How do you know the OP is not asking about how to implement spell check in CRichEditCtrl?

Best wishes,
Hans

[Hans Dietrich Software]

Re: red squiggly line - misspelt words

Albert Holguin13-May-11 13:13

Albert Holguin

13-May-11 13:13

good point, I don't....

Re: red squiggly line - misspelt words

Mark Salsbery13-May-11 14:03

Mark Salsbery

13-May-11 14:03

How does anyone know...

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: red squiggly line - misspelt words

Hans Dietrich13-May-11 20:09

Hans Dietrich

13-May-11 20:09

Mark Salsbery wrote:
How does anyone know...

You really never do. That's why God made else. Smile | :)

Best wishes,
Hans

[Hans Dietrich Software]

Re: red squiggly line - misspelt words

C^hris L^osinger14-May-11 5:32

C^hris L^osinger

14-May-11 5:32

you will have to draw it yourself, if you want such a thing.

image processing toolkits | batch image processing

detect memory leak by _CrtDumpMemoryLeaks();

includeh1013-May-11 2:57

includeh10

13-May-11 2:57

As in link: http://msdn.microsoft.com/en-us/library/e5ewb1h3%28v=VS.80%29.aspx[^]

I defined

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>

and call _CrtDumpMemoryLeaks() in 2 places:

place 1. from a menu Item.
in this case, I see leaking info as:

Detected memory leaks!
Dumping objects ->
{3443} normal block at 0x02EE9BF8, 373376 bytes long.
 Data: <                > C0 C0 C0 C0 C0 C0 00 00 00 00 00 00 00 00 00 00 
afxtempl.h(330) : {3273} normal block at 0x01DCD530, 4 bytes long.
 Data: <(   > 28 10 07 02 
strcore.cpp(118) : {3272} normal block at 0x01DCF2A0, 22 bytes long.
 Data: <            H a > 01 00 00 00 04 00 00 00 04 00 00 00 48 00 61 00 
//more...
E:\Develops\MyProgram\MyUser.cpp(101) : {3258} client block at 0x01DCF890, subtype 0, 152 bytes long.
a CWnd object at $01DCF890, 152 bytes long
strcore.cpp(118) : {3256} normal block at 0x01DCE130, 22 bytes long.
 Data: <            N e > 01 00 00 00 04 00 00 00 04 00 00 00 4E 00 65 00 
//more...

I think info above is not meaningful because app has not exited and many operator "new"s have not been deleted.

place 2. at exit point (MFC - destructor of CWinApp's subclass)
this time, I still see

Detected memory leaks!
Dumping objects ->
{3473} normal block at 0x01DA20C0, 28 bytes long.
 Data: <    !Ce         > BC DF AF AB 21 43 65 87 83 00 00 00 00 00 00 00 
{3443} normal block at 0x02EE9BF8, 373376 bytes long.
 Data: <                > C0 C0 C0 C0 C0 C0 00 00 00 00 00 00 00 00 00 00 
//more...

But, this time, there is no any info about my program files, such as in case 1:

E:\Develops\MyProgram\MyUser.cpp(101) : {3258} client block at 0x01DCF890, subtype 0, 152 bytes long.
a CWnd object at $01DCF890, 152 bytes long
strcore.cpp(118) : {3256} normal block at 0x01DCE130, 22 bytes long.
 Data: &lt;            N e &gt; 01 00 00 00 04 00 00 00 04 00 00 00 4E 00 65 00

My Q is:
Does info in place 2 mean that my program has no memory leaks because there are no my files there?
Or how to find solution without my files related info?

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.