C / C++ / MFC Discussion Boards

Joaquín M López Muñoz21-Sep-02 8:31

21-Sep-02 8:31

Maybe you can take advantage of a technique called HTTP tunneling. Alex Turc describes it in his article HTTP Tunneling[^].

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

shared memory and MFC

nss21-Sep-02 2:37

nss

21-Sep-02 2:37

I found two CP classes for memory mapping but no description or background. Basicallly I have a VC client and a VB COM dll. The dll will be writing to shared memory and the VC client should read it instantly. What informs the process that the memory is ready for reading? There wont be any atual file on disk or anything. I just want to send an integer over from the dll tothe client. I tried sendmessage but it didnt work for some reason. So I'd appreciate it if you can point me to some links where they do what I want.....

Re: shared memory and MFC

Pavel Klocek21-Sep-02 2:47

Pavel Klocek

21-Sep-02 2:47

Shared memory is a memory, that can be mapped to many processes adress space, thats all. Synchronization between processes using it is in your hands.

nss wrote:
I just want to send an integer over from the dll tothe client
That's really not optimal to use shared memory to do it. If you can't use sendmessage for it, try to send an COM event from your COM object.

Pavel
Sonork 100.15206

Re: shared memory and MFC

Joaquín M López Muñoz21-Sep-02 8:25

Joaquín M López Muñoz

21-Sep-02 8:25

You can use named events (see CreateEvent): When data is written the DLL can just set it and all the app has to do is WaitForSIngleBoject for the event.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Header file needed

Ghasrfakhri20-Sep-02 21:16

Ghasrfakhri

20-Sep-02 21:16

Hello everybody
I want to use Internet Authentication Service But AuthIf.h header file is not in my VS 6 package,where can I find it & its libery files?
tnX alot

Iman Ghasrfakhri

Re: Header file needed

Michael Dunn20-Sep-02 21:25

Michael Dunn

20-Sep-02 21:25

See the VC Forum FAQ, it lists where to get the Platform SDK.

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
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Incorporating 16-bit, 32-bit, and 64-bit ASM in C++ :: ASM

valikac20-Sep-02 18:59

valikac

20-Sep-02 18:59

Hi.

I am a C++ programmer.

I began learning 16-bit ASM and practice 16-bit ASM programming under DOS and MASM 6.x three weeks ago. I am very impressed with ASM and the control and simplicity ASM brings to programming. 16-bit ASM is so simple. Programmers have the most flexibility in terms of program design. I enjoy ASM programming and will definitely continue learning and practicing 16-bit ASM.

I have some basic, but essential, questions on implementing 16-bit, 32-bit, and 64-bit assembly in C++ programs.

1) Under what circumstances in additional to device drivers development do programmers use 16-bit and 32-bit ASM? I am most interested in 16-bit ASM when using ASM only.

2) Under what circumstances do C++ programmers incorporate 16-bit and/or 32-bit ASM in C++ programs? Please be as specific as possible. For example, under what conditions do 16-bit and 32-bit ASM out-perform C++? I am most interested in the Windows environment when using C++ and ASM.

Is it possible to apply 16-bit ASM in C++ Windows programs? Again, C++ does all the messaging. I want to incorporate ASM it is called for.

Thanks,
Kuphryn

Re: Incorporating 16-bit, 32-bit, and 64-bit ASM in C++ :: ASM

Mike Nordell21-Sep-02 1:34

Mike Nordell

21-Sep-02 1:34

kuphryn wrote:
Under what circumstances in additional to device drivers development do programmers use 16-bit and 32-bit ASM?

IA16 assembler is used mostly for writing bootsector code.

IA32 assembler is used whenever the compiler can't provide the speed, or instructions, needed to perform a given task at a given speed. F.ex. compilers usually don't (never?) generate e.g. MMX code for plain C/C++.

Is it possible to apply 16-bit ASM in C++ Windows programs?

Yes. Ever version of windows up to (not including) Windows 4.0 (Windows 95) was completely 16-bit. Win9x uses a lot of 16-bit code internally, and is actually more of a 32-bit shell on top of a 16-bit OS than anything else. For Windows version based on the NT kernel the only trace of 16-bit code you'll find is AFAIK the boot loader.

Tweaking your question a bit to read "Is it even remotely useful to apply 16-bit ASM ...", the answer becomes: No. Why on earth would anyone want to punish themselves with that horror?

Re: Incorporating 16-bit, 32-bit, and 64-bit ASM in C++ :: ASM

valikac21-Sep-02 6:27

valikac

21-Sep-02 6:27

Okay.

You made a very good point about how recent versions of Windows make little use of 16-bit ASM. I believe 16-bit ASM is good for use in pure DOS and to communicate directly with hardware in pure DOS mode. In that case, how does 16-bit ASM come into effect? Can you use 32-bit or 64-bit ASM to communicate with hardware?

Kuphryn

Re: Incorporating 16-bit, 32-bit, and 64-bit ASM in C++ :: ASM

Mike Nordell21-Sep-02 11:03

Mike Nordell

21-Sep-02 11:03

kuphryn wrote:
Can you use 32-bit or 64-bit ASM to communicate with hardware?

Since you can express anything in assembler that you also can do with another language (usually with much more work in assembler though), and any Win32 hardware device driver is written in (combinations of) C/C++/assembler, obviously you can communicate with hardware using assembler.

For 64-bit I feel I have to ask: Do you really know anyone even having seen a live Itanium Windows system, much less owns one?

Xtras for Director and XtraBuilder

nencini20-Sep-02 17:25

nencini

20-Sep-02 17:25

I'm learning to buid Xtras for Director
with XtraBuilder (that's a very good
tool for beginners) and Visual C++,
before starting studying XDK.

Simply I ask if somebody know if there
is somewhat similar to XtraBuilder for
Mac and Codewarrior. - Many thanks.

c to c++ for VB calling

DC20-Sep-02 16:37

20-Sep-02 16:37

I use VB.NET or VB6 to call a DLL routine which is written in C (WinPCap). It has "bad calling convention" error. I check the C code and found that it has code for EXPORT in def file but it doesn't has "extern..." or "__stdcall" code in calling function. So, I change

BOOLEAN PacketGetAdapterNames(PTSTR pStr,PULONG BufferSize)

to

extern "C" { __declspec(dllexport) BOOL __stdcall packetfunc(PTSTR s, PULONG BufferSize)
.
.
}

I compile the orginal code ('C' Code) without any error but when I compile the new code (add extern and __stdcall) either in C/C++. I got a lot of error such as "missing string", missing ";". Quite Strange. Anyone has idea ?

Orginal C file is in this link:

http://winpcap.polito.it/install/bin/WPcapSrc_2_3.zip

Many Many Thanks
Danny

question ?

imran_rafique20-Sep-02 15:33

imran_rafique

20-Sep-02 15:33

if i have the DWORD for example
DWORD temp;
i want to set the value of each byte seperately how to set it.
i want to get the value of each byte seperately how to get it.

r00d0034@yahoo.com

Re: question ?

C^hris L^osinger20-Sep-02 16:26

C^hris L^osinger

20-Sep-02 16:26

to set

DWORD dw = 0;
BYTE a = 2;
BYTE b = 3;
BYTE c = 4;
BYTE d = 8;

dw = a;
dw = dw << 8;
dw |= b;
dw = dw << 8;
dw |= c;
dw = dw << 8;
dw |= d;

to get:

BYTE a,b,c,d;
a = dw & 0x000000ff;
b = (BYTE)((DWORD)(dw & 0x0000ff00) >> 8);
c = (BYTE)((DWORD)(dw & 0x00ff0000) >> 16);
d = (BYTE)((DWORD)(dw & 0xff000000) >> 24);

-c

As always, it's bread and circuses. And while bread is down right now, circuses are way up.

War Pigs

Re: question ?

valikac20-Sep-02 16:35

valikac

20-Sep-02 16:35

Nice!

Hey, is it possible to use ASM to get and/or set individual bytes from larger datatype such as WORD, DWORD, etc? Understand this situation, how does ASM performance compared to normal C/C++ solution?

Kuphryn

Re: question ?

Michael Dunn20-Sep-02 16:51

Michael Dunn

20-Sep-02 16:51

Yes, but doing so will not get you anything because the C bitwise operators translate exactly into assmbly instructions like AND, OR, SHL (shift left), etc.

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Re: question ?

valikac20-Sep-02 17:33

valikac

20-Sep-02 17:33

Okay. Well, ASM concepts and syntax are easier to remember than C/C++. There is not reference required for the most part.

Kuphryn

Re: question ?

Michael Dunn20-Sep-02 19:45

Michael Dunn

20-Sep-02 19:45

I guess whichever language you learned first is easier. Wink | ;)

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Re: question ?

Rene De La Garza20-Sep-02 16:45

Rene De La Garza

20-Sep-02 16:45

one question.
when you set the values
a = most significant byte
d = less significan byte

And when you get them
a = less significant byte
d = most significant byte
is this correct?

Re: question ?

Nish Nishant20-Sep-02 18:58

Nish Nishant

20-Sep-02 18:58

Myself wrote:
is this correct?

Yup Smile | :)

Author of the romantic comedy

Summer Love and Some more Cricket [New Win]

Review by Shog⁹
Click here for review[NW]

Re: question ?

Nish Nishant20-Sep-02 18:57

Nish Nishant

20-Sep-02 18:57

Just one point (in case Imran is confused)

In Chris L's "set" example, a is the MSByte and d is the LSByte

In his "get" example, he's kinda reversed it so that :-
a is the LSByte and d is the MSByte

Thought I'd mention it here.

Regards,
Nish

Author of the romantic comedy

Summer Love and Some more Cricket [New Win]

Review by Shog⁹
Click here for review[NW]

Re: question ?

Ed Gadziemski21-Sep-02 3:08

Ed Gadziemski

21-Sep-02 3:08

Don't you like the MAKELONG and MAKEWORD macros?

Answer

Ghasrfakhri20-Sep-02 21:33

Ghasrfakhri

20-Sep-02 21:33

u can use this structur & union to do it
union {
DWORD a;
struct {
_1:1;
_2:1;
_3:1;
_4:1;
_5:1;
_6:1;
_7:1;
_8:1;
_9:1;
_10:1;
_11:1;
_12:1;
_13:1;
_14:1;
_15:1;
_16:1;
}bits;
}DW;

you can use that struct

to set a bit first palce your DWORD var to "DW.a" then set bits:
DW.a = YourVar;
DW.bits._1 = 1;//set the first bit to one
DW.bits._2 = 0;//set th second bit to zero
.
.
.

YourVar = DW.a;

Rose | [Rose]

Iman Ghasrfakhri

Re: question ?

PJ Arends21-Sep-02 9:54

PJ Arends

21-Sep-02 9:54

http://www.codeproject.com/cpp/bitbashing.asp

CPUA 0x5041

Sonork 100.11743 Chicken Little

"So it can now be written in stone as a testament to humanities achievments "PJ did Pi at CP"." Colin Davies

Within you lies the power for good - Use it!

Linker errors

monrobot1320-Sep-02 15:17

monrobot13

20-Sep-02 15:17

When I compile my program I keep getting errors that some symbols are multiply defined. The items in question are in a global hearder file that each class needs to include so I assume this is where the problem exists, in that the file is being included into every class and producing the errors. I tried putting include guards on the header file but it doesn't change anything. Any help in this matter would be much appreciated.

Thanks in advance.

- Monrobot13

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