Re: real simple question - C / C++ / MFC Discussion Boards

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Re: Thread Probs (again)

MarkPQ5-Mar-02 17:43

MarkPQ

5-Mar-02 17:43

Thanks for the reply,

This is what I'm calling to start the thread:
HANDLE myConnectThread = AfxBeginThread(ConnectThread, (LPVOID)this);

So how would I change it to pass it the hWndParent? Also how do I get the hWndParent value?? is it this->m_hWnd??? This whole handle thing has got me slightly confused.

Also I know how the parent needs to clean up the CString! A helpful person from here has already brought it to my attention!

Is there any better way of doing all this though?? I mean because these threads are static I obviously cant access the member variables of the dialog class directly. Is there other ways of making threads where I could be able to do this? I see there are other ways of meaking threads ie: CreateThread or _beginThread, whats the difference with the one I'm using and which would be betst?

Thanks
-Mark

Re: Thread Probs (again)

MarkPQ5-Mar-02 17:57

MarkPQ

5-Mar-02 17:57

Ok I've got the function working with this:

HANDLE myConnectThread = AfxBeginThread(ConnectThread, (LPVOID)this->m_hWnd);

And in the thread:

UINT AlstomSerial::ConnectThread(LPVOID pParam)
{
::PostMessage((HWND)pParam, wm_Message, (WPARAM)0, (LPARAM)ps);
}

This feels a bit dodgy to me?? Anyone suggest a better way of doing this??

Re: Thread Probs (again)

5-Mar-02 18:24

That seems about right. You may want to call ::IsWindow((HWND)pParam) first just to make sure the handle is valid. The parent window may have exited/died before the thread gets its hands on it. Stranger things have happened, and when multithreading, playing safe is a must.

Double buffer example

alex.barylski5-Mar-02 15:45

alex.barylski

5-Mar-02 15:45

Anybody know any good explanations of the inner workings of double buffering to remove flicker...?

I'm using the CMemDC class right now, but am currently experiencing problems, so i'd like to tackle the problem line by line and just do it manually.

I get the gist of it and even implemented it, but I used a bitmap from resource instead of creating it dynamically using CreateCompatibleBitmap. I'm doing something wrong and would like to see an exmaple of how to do it fom start to finish.

I'm aware of the classes currently on CP, but would like an explanation of double buffering with a small example I can pick apart and figure out what i'm doing wrong.

CreateCompatibleDC
CreateCompatibleBitmap
Select compatible bitmap into compatible DC
LineTo on compatible DC
BitBlt compatible bitmap to original DC

What am I missing here...?

Thanx a bunch!

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: Double buffer example

Tomasz Sowinski6-Mar-02 0:04

Tomasz Sowinski

6-Mar-02 0:04

Looks OK. Just remember to call CreateCompatibleBitmap for original DC, not the compatible, in-memory one.

Tomasz Sowinski -- http://www.shooltz.com

real simple question

5-Mar-02 15:32

ok this is vexing me

i have a string like this:

blahblahblahblah$blahblahblahblah$

notice is contains $ characters.

i want to SPLIT this string using the $ as a delimiter.

The string is stored in a CString (i'm using MFC).

Can someone show me how I can tokenize this string. A SIMPLE example please!!!

ARGH, thanks!!

Re: real simple question

alex.barylski5-Mar-02 16:02

alex.barylski

5-Mar-02 16:02

CString buff("This is$my string");

for(int x=0; x<<buff.GetLength(); x++)
{
  if(buff.Find('$', x)){  //$ found
    CString strSplitLeft = buff.Left(x-1);
    CString strSplitRight= buff.Right(x+1);
  }
}

Notice this only splits a string in half nothing more. It find the first $ character and copies anything left of it to a buffer and anything right of it to another buffer.

It would reauire a littel tweaking to split a string multiple times.

Cheers!

p.s-Ignore the << it should only be one...but I don't know the excape code in HTML for single angle brackets. Sorry!

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: real simple question

Michael Dunn5-Mar-02 16:28

Michael Dunn

5-Mar-02 16:28

Use the undocumented function AfxExtractSubString().

int n = 0;
CString sToken;
 
  while ( AfxExtractSubString ( sToken, sBlahBlahString, n++, '$' ))
    {
    // do stuff with the token ...
    }

--Mike--
Best score on the mini-putt game: 26
My really out-of-date homepage
Sonork - 100.10414 AcidHelm
Big fan of Alyson Hannigan and Jamie Salé.

Re: real simple question

5-Mar-02 16:42

omg thanks been looking for a simple way like that!!!!

Re: real simple question

alex.barylski5-Mar-02 17:53

alex.barylski

5-Mar-02 17:53

Cool...that is easy!

Thanx Mike!

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: real simple question

Todd.Harvey6-Mar-02 9:13

Todd.Harvey

6-Mar-02 9:13

I wish we could rate these posts like you can at CodeGuru - what a helpful post! Laugh | :laugh:

Whats wrong with this?

SilverShalkin5-Mar-02 14:01

SilverShalkin

5-Mar-02 14:01

Please help, whats wrong with this code?
"if statment"

char r;
gets(r);
if (r == "ok")
{
cout << ("good job");
}

What wrong with that? how can i make it work?

Thanks!

~SilverShalkin

ps... im new to this forum, so if you see another thread like this one, im sorry
didnt mean to. Smile | :)

Programming is an art, dont spoil it with work.

Re: Whats wrong with this?

Lofote5-Mar-02 14:26

Lofote

5-Mar-02 14:26

Uh, a lot. First of all, "char" is a single character, not a whole string. You need to do an char array for a complete string, or use a CString from MFC. Second, you can't compare char arrays with the "==" symbol, you need to use "strcmp" ("==" does work for CStrings however).

So, correct code would look something like this:

char r[256]; //note that if user inputs more than 255 characters, program might crash
gets(r);
if(strcmp(r,"ok")==0)
{
cout << ("good job");
}

Cya (c:

Re: Whats wrong with this?

Christian Graus5-Mar-02 14:27

Christian Graus

5-Mar-02 14:27

Lofote wrote:
or use a CString from MFC.

Or in this case, use std::string seeing as MFC is not being used anywhere else in the code.

Lofote wrote:
Second, you can't compare char arrays with the "==" symbol,

Really ?

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

Re: Whats wrong with this?

SilverShalkin5-Mar-02 14:49

SilverShalkin

5-Mar-02 14:49

you cant compare char arrays with "==", then how do you do it?

Thanks

~SilverShalkin

What little life a rose may give, its the buety that will last forever.

Re: Whats wrong with this?

Jon Sagara5-Mar-02 14:49

Jon Sagara

5-Mar-02 14:49

With the strcmp() function.

Jon Sagara

What about ?

Sonork ID: 100.9999 jonsagara

Re: Whats wrong with this?

Rohit Sinha5-Mar-02 15:11

Rohit Sinha

5-Mar-02 15:11

Jon Sagara wrote:
With the strcmp() function.

or even lstrcmp(), if you want to use the Win32 api to do it.

impuzible

Re: Whats wrong with this?

Jon Sagara5-Mar-02 15:25

Jon Sagara

5-Mar-02 15:25

or _tcscmp(). Poke tongue | ;-P

Jon Sagara

What about ?

Sonork ID: 100.9999 jonsagara

Re: Whats wrong with this?

Tim Smith5-Mar-02 15:30

Tim Smith

5-Mar-02 15:30

I always liked being nice the the user...

_tcsicmp

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

Re: Whats wrong with this?

Jon Sagara5-Mar-02 15:36

Jon Sagara

5-Mar-02 15:36

Bah - let 'em suffer, I say!

Jon Sagara

What about ?

Sonork ID: 100.9999 jonsagara

Re: Whats wrong with this?

Christian Graus5-Mar-02 14:56

Christian Graus

5-Mar-02 14:56

Ultimately, char arrays are ugly C, and also not safe, as has been noted. You'll end up using CString or std:string just like everyone else, but for some reason the books all take a low to high approach which shows you the std library AFTER you've learned things the unnecessarily hard way.

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

Re: Whats wrong with this?

Tim Smith5-Mar-02 15:09

Tim Smith

5-Mar-02 15:09

People should still learn how to use C strings. They are very powerful and VERY safe when used properly.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

Re: Whats wrong with this?

Christian Graus5-Mar-02 15:14

Christian Graus

5-Mar-02 15:14

Tim Smith wrote:
People should still learn how to use C strings.

Absolutely - I just dispute the idea they should learn it first...

Christian

The tragedy of cyberspace - that so much can travel so far, and yet mean so little.

Re: Whats wrong with this?

Tim Smith5-Mar-02 15:17

Tim Smith

5-Mar-02 15:17

Woops, my fault then. I misunderstood you.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

Re: Whats wrong with this?

SilverShalkin5-Mar-02 14:57

SilverShalkin

5-Mar-02 14:57

Lofote wrote:
char r[256]; //note that if user inputs more than 255 characters, program might crash
gets(r);
if(strcmp(r,"ok")==0)
{
cout << ("good job");
}

Thanks man, although i did change the character memory amount to 255. The if statment worked!

This is awesome, thank you allot. Ill let the help files help me with how it works, and i may see you all later.

~SilverShalkin

The perfect puzzle, Programming.

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