C / C++ / MFC

26-Dec-01 11:07

Override
CFormView::OnCreate

I vote pro drink Beer | [beer]

UINT 1 or 2 bytes?

26-Dec-01 10:41

I've tried to convert a UINT to char and back again, it doesnt work, how many bytes in one UINT and how many bits per byte?
This sounds to be very simple but I'm not having luck!

Tim Smith26-Dec-01 11:12

Tim Smith

26-Dec-01 11:12

Are you talking about a VC6 compiler?

Then UINT is 4 bytes. Each byte is 8 bits.

A char is a SIGNED 1 byte value.

What part of the conversion doesn't work? Aside from syntax error and loss of precision or funny business with the sign bit, there isn't anything that can actually fail.

Tim Smith
Descartes Systems Sciences, Inc.

26-Dec-01 11:52

The loss of precision was teh problem, i'm attempting to use the code in (Strange effects with bitwise operators to solve this)

26-Dec-01 12:16

I simply needed to do this to write a UINT to a 1 byte buffer, so i could save this value!

Sprudling26-Dec-01 17:12

Sprudling

26-Dec-01 17:12

Since an UINT it 4 bytes, it's impossible to cast it to a char (1 byte) without losing precision. Of course if the 24 highest bits (the 3 "leftmost" bytes) of the UINT are all zeroes, no information would be lost. The value may differ thought, since UINT is unsigned, and char is not; i.e. it's signed) Casting from char to UINT however should never give you any trouble.

Jason M wrote:
I simply needed to do this to write a UINT to a 1 byte buffer, so i could save this value!

Ok, you want to save this value, but why not save it in a 4 byte buffer, which is how much an UINT requires?

Sprudling Smile | :)

moliate27-Dec-01 19:13

moliate

27-Dec-01 19:13

Just a quick note. When working with a datatype, you should never assume what size they are. Use sizeof(..) to get the storage space in bytes.

/moliate

UINT 1 or 2 bytes?

26-Dec-01 10:38

I've tried to convert a UINT to char and back again, it doesnt work, how many bytes in one UINT and how many bits per byte?

Nemanja Trifunovic26-Dec-01 10:59

26-Dec-01 10:59

UINT - A 16-bit (2 bytes) unsigned integer on Windows versions 3.0 and 3.1; a 32-bit (4 bytes) unsigned integer on Win32.

I vote pro drink Beer | [beer]

26-Dec-01 11:12

cheers mate!

COM?

Rickard Andersson²⁰26-Dec-01 10:24

Rickard Andersson²⁰

26-Dec-01 10:24

Ok, now I want to know what COM is!!
Or I just want to make it clear, my thought is that a COM -> OBJECT <- is a varible:

CAClass com; // COM object???

No, I don't think so...

What HOW do I make a COM object for example??
I don't realy know how it looks like! Frown | :(

(

------------------------------
©0d3 ©®4©k3® - That's me! Smile | :)

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Re: COM?

Nemanja Trifunovic26-Dec-01 10:34

26-Dec-01 10:34

Rickard Andersson wrote:
Or I just want to make it clear, my thought is that a COM -> OBJECT <- is a varible:

CAClass com; // COM object???

No, I don't think so...

VERY simplified:

<br />
class COMInterface<br />
{<br />
public:<br />
virtual method1 = 0;<br />
virtual method2 = 0;<br />
};<br />
<br />
class COMCoClass: public COMInterface<br />
{<br />
method1;<br />
method2;<br />
}<br />
<br />
int main(void)<br />
{<br />
...<br />
COMInterface* pInterface;<br />
// call CoCreateInstance, or something like that<br />
...<br />
pInterface->method1;<br />
...<br />
}<br />
<br />

I vote pro drink Beer | [beer]

Re: COM?

Michael Dunn26-Dec-01 14:36

Michael Dunn

26-Dec-01 14:36

http://www.codeproject.com/com/comintro.asp

--Mike--
My really out-of-date homepage
Buffy's on. Gotta go, bye!
Sonork - 100.10414 AcidHelm
Big fan of Alyson Hannigan.

VB and COM

Mazdak26-Dec-01 8:17

Mazdak

26-Dec-01 8:17

I have general question about COM developing in VB.
Does Visual Basic have something like ATL for COM developing(except ActiveX)?(I mean something like "simple object"in ATL)
VB doesn't have pointers ,so How does it implement interfaces,methods and another things in COM.
Are COMs that design in VB as strong as,as fast as or... COMs that in ATL have?

Re: VB and COM

Carlos Antollini26-Dec-01 8:36

Carlos Antollini

26-Dec-01 8:36

When you make a com object in something named VB, you not write the IDL. The interface is generated by the VB compiler...
In same mode is easy to write com objects in VB, but the problem is that you don't have the control like in ATL projects when you write the IDL file...

Best Regards...

Carlos Antollini.
Sonork ID 100.10529 cantollini

Re: VB and COM

Nemanja Trifunovic26-Dec-01 9:01

Read/Write Com Port :: C++

26-Dec-01 9:01

Everything in VB 4/5/6 is COM. If you create a new project as an ActiveX DLL or ActiveX EXE, you will have COM servers, and all you need to do is to fill in the methods you want. Everything else is done by the compiler.

However, COM servers created with VB depend on VB runtime, and they can never be lean and fast as ATL created.

I vote pro drink Beer | [beer]

valikac26-Dec-01 6:06

26-Dec-01 6:06

Hi.
Is it easy to read from and write to the com port using C++? Is there a library for it?

Thanks,
Kuphryn

Hadi Rezaee26-Dec-01 9:49

Hadi Rezaee

26-Dec-01 9:49

Try CreateFile or OpenFile API functions ...

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

Hadi Rezaie

valikac26-Dec-01 14:16

26-Dec-01 14:16

Okay. Thanks.

Felix posted a reply at Programmer's Heaven and mentioned functions:

inp();

and

outp();

http://www.programmersheaven.com/msgboard/read.asp?Board=3&MsgID=93124&Setting=A9999F0001

Those functions are from conio.h. What do you think about those functions?

Kuphryn

Mattias Wahlberg26-Dec-01 20:20

Mattias Wahlberg

26-Dec-01 20:20

kuphryn wrote:
inp();

and

outp();

http://www.programmersheaven.com/msgboard/read.asp?Board=3&MsgID=93124&Setting=A9999F0001

Those functions are from conio.h. What do you think about those functions?

They are old and you are probably better of using a modern class-library or perhaps an Active-X component like GreenLeaf CommX. I am in no way connected to Green Leaf but I have successfully used thier products for 10 years on all OS:es from DOS, OS/2 to Windows 3.11/95/NT/2000. Their site is at http://www.gleaf.com/

--
Mattias Wahlberg
IDNet

Hadi Rezaee27-Dec-01 21:08

Hadi Rezaee

27-Dec-01 21:08

Hi,
Unfortunly, thease functions can't works on Win NT !

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

Hadi Rezaie

Diferences: MFC and Non-MFC

Eugene Pustovoyt26-Dec-01 19:21

Eugene Pustovoyt

26-Dec-01 19:21

On this site there are some libraries for work with CommPort.

1. Ramon de Klein's Serial library for C++
2. PJ Naughter's CSerialPort v1.03 - Serial Port Wrapper
(or better on your site, there the newest version).

Personally I use the second!

Best regards,
Eugene Pustovoyt

Sonork ID 100.10002:Yaumen

valikac28-Dec-01 5:41

28-Dec-01 5:41

Hey.

I read Ramon de Klein's description of Serial library for C++. It sounds good.

PJ Naughter's class is a for MFC.

What is the difference between, say, Klein's class and Naughter's class?

What is the advantage of using MFC and not non-MFC?

Kuphryn

valikac27-Dec-01 6:57

27-Dec-01 6:57

Okay. I appreciate it. Thanks everyone.

Kuphryn

valikac27-Dec-01 7:02