Re: Byte Alignment - C / C++ / MFC Discussion Boards

[CoY0te]13-Aug-02 1:46

13-Aug-02 1:46

Yo've missed one little thing:
You have: "%%.%f", and You should have "%%.%df"
And of course signif must be an integer value;
"%%.%f" tries to interpret your signif as floating poin value and it doez not produce the f char for m_nMorality.
"%%.%df" will produce "%.<signif>f"

[ CoY0te ]
Railgun is like a Gilette Mach 3 - it does the job with one, easy stroke.

Re: CString Format method

jbarton13-Aug-02 2:50

jbarton

13-Aug-02 2:50

Hi,

The easiest way to do this is to use the '*' modifier in your format string. This allows you to specify the number of digits with a variable.

The following will format using a variable number of digits:

int precision = 5;
x.Format( _T("%.*f"), precision, number );

You can also use a * for the width of the field, so the following will set the width and precision:

int width = 10;
int precision = 3;
x.Format( _T("%*.*f"), width, precision, number );

Best regards,
John

Byte Alignment

solosnake12-Aug-02 23:17

solosnake

12-Aug-02 23:17

Hello

I'm having some problems with byte alignment. I'm writing a graphics editor for particle effects for games. The effects are edited on a PC and exported to a file which is read by a PlayStation2. The code for the PS2 is compiled under GCC, the editor with VC++ 6.0 (Service Packs installed).

For memory reasons I want to be able to use the file I load as the structure directly, so it must be stored witht the correct byte alignment to be correctly read by the PS2 (and to benefit from possible later VPU optimisations). I have set the VC++ project settings to be 16 byte aligned by default. I have also used #pragma pack(16) before critical structures.

I noticed however that for some x87 asm I wrote that the structures were not being 16 byte aligned. VC++ seemed to be completely ignoring ALL my efforts to force it to align structures.

Now when reading the structure, if I tell gcc that the structure is 16-byte aligned (using the __attribute__(align(16)) directive) the structure is read incorrectly. If VC++ had written my structure with 16 alignment this should not be the case? However when I switch off the alignment directive on gcc the struct is loaded correctly.

My questions are:
1)
How can I declare a structure in VC++ such that it will have specific alignement? I think it is as follows:
#pragma pack(16) or #pragma pack(push,16) followed by #pragma pack(pop) bracketing the struct declaration. But my experience seems to be to the contrary.

2) How can I check this is actually working?
3) How can I check the alignment of a pointer at runtime?

If anyone has any experiences in this area, and want to tell me about them, please do!

Thanks to anyone who helps,

- solosnake

Re: Byte Alignment

Tomasz Sowinski13-Aug-02 0:40

Tomasz Sowinski

13-Aug-02 0:40

Can you check the size of your struct with sizeof at runtime?

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

What is "scratch" and why can everything be made from it?

Re: Byte Alignment

Anonymous13-Aug-02 1:07

Anonymous

13-Aug-02 1:07

Yes I can, by creating a temporary and examining. Is the idea to see if it changes in VC++ when I change alignment? I'll give it a go.

- solosnake

Re: Byte Alignment

Brian Azzopardi13-Aug-02 4:03

Brian Azzopardi

13-Aug-02 4:03

In my code I use

#define CACHE_LINE  32<br />
#define CACHE_ALIGN __declspec( align(CACHE_LINE) )

to align a variable on the 32byte boundry so that it is AGP cache aligned (I'm writing a game at the mo.). Change the above to 16. Should work.

BTW, how is the Linux Kit for the PS2? Is it any good? I'm thinking of getting it but I'm currently too busy with Opengl to get a crack at the PS2.

bibamus, edamus, cras moriemur

[eat, drink, for tomorrow we die]

Re: Byte Alignment

JT Anderson13-Aug-02 6:45

JT Anderson

13-Aug-02 6:45

Disclaimer: The following statement is not exactly true, but it's close enough for the purpose of this discussion.

#pragma pack only affects the packing of things larger than the specified size. Things smaller than the specified size are packed on their natural boundaries. For example, pragma pack(2) will cause ints, longs and __int64s to be packed on 2-byte boundaries, but won't affect the packing of chars (one-byte boundaries) or shorts (2-byte boundaries in any case).

Perhaps if you were to show us your structure, we'd be able to tell you why you are not getting the expected results.

Under the circumstances, you may want to use pragma pack(1) and put explicit padding in your structure.

Re: Byte Alignment

solosnake14-Aug-02 1:44

solosnake

14-Aug-02 1:44

Hello

This structure causes problems when the PFXVector3 struct is declared with __attribute__(align(16)) in gcc, even when VC++ is set to align on 16 byte boundries.

struct PFXVector3 {<br />
    F32                     x,y,z;<br />
};<br />
<br />
struct PFXEffectBaseData {<br />
    U32                     m_uiLifeTime;<br />
    U32                     m_uiAge;<br />
    U32                     m_uiFlags;    <br />
    CMatrix4                m_matrixRotate;<br />
    PFXVector3              m_v3dGravity;<br />
    PFXVector3              m_v3dPosition;<br />
};

U32 is just a typedef for unsigned 32 bit ints.
F32 is typedef for 32 bit single prec. fp.
CMatrix4 is the house matrix class.

To Brian:
>BTW, how is the Linux Kit for the PS2? Is it any good? I'm thinking of getting it but I'm
>currently too busy with Opengl to get a
>crack at the PS2.

I'm using SN Systems and a genuine Sony Dev Kit here at work. But sometimes I wish I was at home with a Linux Kit Smile | :)

And doing OpenGL....sigh....

Thanks for all feedback again to everyone

- solosnake

1. Simple techniques for dragging/sizing controls | 2. Non cubical dialogs/controls

BlackSmith12-Aug-02 23:08

BlackSmith

12-Aug-02 23:08

1.
I've CEdit and a CButton on a CDialog. The CButton placed on top of the
CEdit. When the CButton is dragged up/down, I wish the CEdit will
streach/shrink, corresponding to the CButton bottom coordinate.

CAN SOMEONE LINK ME TO SOME ARTICLE THAT CAN RESOLVE MY ISSUE???

2.
An article dealing with HOWTO create non-cubical windows/controls (please?)

10XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX a lot

--BlackSmith--

"With the help of all mighty", 2001, Me.

Database Connection with SDK

vin12-Aug-02 22:36

vin

12-Aug-02 22:36

Hi,

Can any one tell me the API's for database connection with SDK. Is there any article which explains this.

Kindly help.

Re: Database Connection with SDK

Ranjan Banerji13-Aug-02 2:38

Ranjan Banerji

13-Aug-02 2:38

I do not believe Windows SDK provides any database connection functionality. You will have to use the ODBC SDK at minimum or native drivers/tools provided by the DBMS vendor or newer connectivity tools likes ADO, OLE DB etc. I am assuming when you said SDK you meant Windows SDK.

Re: Database Connection with SDK

pépé13-Aug-02 3:05

pépé

13-Aug-02 3:05

Hi,

If you use Access, you can use CDao* classes.
hope it helps !

Marking a row in a CListCtrl

Poul Haahr Klemmensen12-Aug-02 22:10

Poul Haahr Klemmensen

12-Aug-02 22:10

After having used CListCtrl::FindItem() to find the index of an item I want to mark the row with that index how do I do that?

I also committed the crime of posting a programming question in the Lounge.

Re: Marking a row in a CListCtrl

567890123412-Aug-02 22:34

5678901234

12-Aug-02 22:34

To select item number i in list control use:
m_list_ctrl.SetItemState(i, LVIS_SELECTED, LVIS_SELECTED);
To ensure that item number i is visible, use:
m_list_ctrl.EnsureVisible(i, FALSE);
If you want full row selection in list control:
m_list_ctrl.SetExtendedStyle ( LVS_EX_FULLROWSELECT );

Re: Marking a row in a CListCtrl

Stefan Pedersen12-Aug-02 22:34

Stefan Pedersen

12-Aug-02 22:34

Mark?
If you by "mark" mean "select" then use the SetCurSel(index) method

Re: Marking a row in a CListCtrl

Stefan Pedersen12-Aug-02 22:37

Stefan Pedersen

12-Aug-02 22:37

Argh! Ignore my previous post, too early in the morning...

what is PeekAndPump()??

tulc_kris12-Aug-02 21:57

tulc_kris

12-Aug-02 21:57

Hi Can someone explain PeekAndPump() function and why should we use it with a ProgressBar??
Is there a standard definition for this function???
Blush | :O

Re: what is PeekAndPump()??

jmkhael12-Aug-02 23:27

jmkhael

12-Aug-02 23:27

Good link http://www.codeguru.com/controls/progress_wnd.shtml

Papa
Murex Co.

while (TRUE)
Papa.WillLove ( Bebe ) ;

Re: what is PeekAndPump()??

Tomasz Sowinski13-Aug-02 0:44

Tomasz Sowinski

13-Aug-02 0:44

The PeekAndPump function you're referring to is probably part of some example. There's no API or MFC function with this name.

Name of this function suggests that there's a loop inside which checks for messages with PeekMessage - hence the 'peek' part. If there's any message, it's dispatched to appropriate window; this is the reason for 'pump'. The peek'n'pump solution is needed because there's some activity going on and progress bar shows the progress of operation.

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

What is "scratch" and why can everything be made from it?

Thread and serial port

Mavrock12-Aug-02 19:25

Mavrock

12-Aug-02 19:25

I am new to programming. I have been given the task of making an application that recieves commands via the serial port. and then displays a notification that the commands were recieved. I have been told that I need to use a thread to do this. I'm not sure where the thread goes, I.E does it go in the source file or the header file? Or do I declare it in the header file and then put the functionality in the OnInitialDialog function?
Thank you for any help.
Mavrock

Re: Thread and serial port

Trollslayer12-Aug-02 22:17

Trollslayer

12-Aug-02 22:17

Mavrock,
I have done something similar but nowhere near doing an article yet.
Basically:
1. Create a dialogue box
2. Insert the Mircosoft communications ActiveX component into it.
3. Create a variable name for the ActiveX component. This then creates a class for the MSCOMM component (prompt displayed).
4. Set the RThreshold property to 1. This causes an OnCommEvent for every character received.
5. In the OnCommEvent() procedure, event 2 is for soemthing received.

If you want a small sample project let me have your email address and I'll forward it.
I have used this on Win98 and NT4 with no problems.

Elaine (fluffy tigress emoticon)

Would you like to meet my teddy bear ?

Re: Thread and serial port

Mavrock13-Aug-02 6:24

Mavrock

13-Aug-02 6:24

Dear Elaine,

Thank you for the direction. If you don't mind I would really like to see your sample project. You can send it to me at stonematthies@hotmail.com.
thanks. Mavrock

Re: Thread and serial port

dlhson13-Aug-02 6:45

dlhson

13-Aug-02 6:45

On this site codeproject.com and on codeguru.com, you can find many articles about your topic

Hung Son
A Vietnamese student
i-g.hypermart.net
dlhson2001@yahoo.com

Other question about Carlos Antollini ADO classes !!!

Hadi Rezaee12-Aug-02 19:13

Hadi Rezaee

12-Aug-02 19:13

Hi there,
I just wanted to add new records to end of record list like this:

Gen
Brus Lee
Arnold
Hadi Poke tongue | ;-P

and etc.

I wrote it:

m_rs.AddNew();
m_rs.SetFieldValue("NAME", "Gen");
m_rs.SetFieldValue("NAME", "Brus Lee");
m_rs.SetFieldValue("NAME", "Arnold");
m_rs.SetFieldValue("NAME", "Hadi");
m_rs.Update();

But when i run this code, the result is strange ...
the result is it:

Hadi
Arnold
Brus Lee
Gen

OMG | :OMG:

vice versa ???
But why ?

What's my wrong ?

Help me please !

Regards,

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Re: Other question about Carlos Antollini ADO classes !!!

C^hris L^osinger12-Aug-02 19:22

C^hris L^osinger

12-Aug-02 19:22

why don't you ask this on Carlos's article ?

Conservative:
One who admires radicals centuries after they're dead.
-- Leo C. Rosten

image effects!

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