C / C++ / MFC

Anders Molin1-Jul-01 7:27

Anders Molin

1-Jul-01 7:27

You need to install MDAC (Microsoft Data Access Components), which you can download from http://www.microsoft.com/data/

I don't know what installer you use, but Installshield have support for installing MDAC silently on the endusers machine...

- Anders

Money talks, but all mine ever says is "Goodbye!"

Chris Klecker1-Jul-01 9:38

Chris Klecker

1-Jul-01 9:38

I found the MDAC module. Downloaded it, and am waiting from other guy to see if it was a success. (confident it will be) so now I looking into having Installshield automatically install MDAC, but I can't seem to find in the help file how Install shield might get this done.

Blush | :O

Thanks for the insight.

Chris

"Why are we hiding from the police, Daddy?"
"We use VI, son. They use Emacs."

Anders Molin1-Jul-01 10:07

Anders Molin

1-Jul-01 10:07

What version of InstallShield are you using?
In "InstallShield Professional for Windows Installer" MDAC is avaliable as a merge module, it's also possible to use their Express version, I just don't remember how, but I can find out.

- Anders

Money talks, but all mine ever says is "Goodbye!"

Chris Klecker1-Jul-01 10:48

Chris Klecker

1-Jul-01 10:48

Install shield for VC++. Comes with the disk. It's not the Professional Edition.

Looks like some of my money is going "Buh-bye!" Wink | ;)

Chris

"Why are we hiding from the police, Daddy?"
"We use VI, son. They use Emacs."

stupid (template related?) linkage puzzle

Anders Molin1-Jul-01 11:58

Anders Molin

1-Jul-01 11:58

Well, I have never tried it with that version. If you download the MDAC SDK, there is a way to install MDAC silent, they talk about it in the readme...
You just need to execute mdac_typ.exe, with the right parameters, from your installer...

- Anders

Money talks, but all mine ever says is "Goodbye!"

New Stream Types

NullStream30-Jun-01 21:43

NullStream

30-Jun-01 21:43

This is a standard C++ question rather than Visual C++ specific.

I'm trying to figure out how to make new types of streams (aka not stdio or file io related) and I'm not sure where to start. A few of the vague articles I read stated I must subclass a streambuf but the member functions are not well named nor well documented. Confused | :confused:

Essentially I'm trying to build a clean portable IPC library (well portable in that the interface is portable Smile | :)

) and the cleanest way I can think of is using customized streams (socket-stream,memory-stream,pipe-stream,memory-mapped-file-stream etc).

Can anyone point me in the right direction or to a suitable article or set of articles? I know there is a book or two out there but the only one suitable is a bit beyond a broke student's resources. I would appricate any assistance in any form.

Sean Cody (NullStream)
"As long as you want to live,
everywhere will become heaven.
Afterall, you are still alive."
- End Of Evanglion

Re: New Stream Types

1-Jul-01 20:03

Let me save you a lot of time. Go out and buy yourself a copy of

"Standard C++ Iostreams and Locales"

By Langer and Kreft.

It discusses in the most minute possible detail how to create your own streambuffer class and use it in a stream.

Basically what you do when you create a streambuffer class is first decide

1. Will it handle input?
2. Will it handle output?
3. Will it handle both simultaneously?

The answer to these questions determines the level of complexity involved in coding it.

Once you have determines that, you then know which functions you need to implement. The functions you implement are PRIVATE VIRTUAL functions. For example, you should not implement 'pubsync' because that it a public, non-virtual function. But you would implement 'sync' because that is a private, virtual function (and generally is what 'pubsync' calls anyway).

The topic is a big one. At the moment, I'm trying to write my own streambuffer for Winsock. I've seen a couple of implementations of this on the web, but I'm doing my own mainly as a learning experience.

Joe O'Leary

Alex Griffing30-Jun-01 20:28

30-Jun-01 20:28

Hi everyone!
I've been programming in C++ for quite a while but I'm just learning the template stuff in the hopes of taking advantage of the STL. Anyway, I have a header file declaring two different classes, one of which is templated. The non-inlined member functions of these classes are defined in the same cpp file. When I try to build the program, the non-inlined member functions of the templated classes give me a linkage error (unresolved external symbol) while the corresponding functions of the non-templated class work fine. Furthermore, if I cut and paste the definitions of the member function of the templated class into the header file then everything links up fine. I know if I keep it like this I'll get reincarnated as a newt. Any suggestions? Confused | :confused:

Michael Dunn30-Jun-01 21:29

Michael Dunn

30-Jun-01 21:29

if I cut and paste the definitions of the member function of the templated class into the header file then everything links up fine.

That's a known problem of the VC compiler. If you are stuck using VC you'll need to organize your code like that, and just look forward to being a newt. Wink | ;)

--Mike--
http://home.inreach.com/mdunn/
"Holding the away team at bay with a non-functioning phaser was an act of unmitigated gall. I admire gall."
-- Lt. Cmdr. Worf

Erik Funkenbusch1-Jul-01 1:22

Erik Funkenbusch

1-Jul-01 1:22

That's the way templates are supposed to work.

The ANSI C++ Committee created a special keyword, called "export" to allow you to put non-inlined functions outside of the translation unit, but no compiler yet supports this (not just VC).

One work around is to #include the .cpp file at the end of your .h file, which is weird, but it will allow you to more easily port it at a later date when "export" becomes supported.

The reason for this has to do with template expansion. Since the template expansion happens in the translation unit that is using the template, that means when your templates cpp file is compiled, it doesn't know what other template instantiations to create.

NullStream1-Jul-01 8:34

NullStream

1-Jul-01 8:34

With templates you have no choice. Frown | :(

Sorry.

I try to keep my paramatized classes as small as humanly possible.

Sean Cody (NullStream)
"As long as you want to live,
everywhere will become heaven.
Afterall, you are still alive."
- End Of Evanglion

Alex Griffing1-Jul-01 13:30

To all readers - I'm collecting FAQs from this forum

1-Jul-01 13:30

This is one of those problems that would have been a nagging doubt for a long time.
Thanks for explaining it to me! Rose | [Rose]

Sliding message window

30-Jun-01 13:58

Hi all,

I am looking for an example demonstrating how to build a sliding window, like the one that slides up above the system tray when a new message comes. If you can provide a link or brief example, you'd really help me out. Thanks in advance.

Michael Dunn30-Jun-01 13:44

Michael Dunn

30-Jun-01 13:44

Hi folks. I decided to start collecting FAQs from this forum, and below is a list of the questions I could remember, along with a really brief answer. I'll expand on the answers in the final FAQ, naturally.
If you can think of any additional ones, please mail them to me at mike@codeproject.com.

Why don't my #include lines show up right in the forum? [Use < and > instead of < >]
I'm trying to call a Windows API, but the compiler gives an undeclared identifier error. What's up? [#define the right values for WINVER, _WIN32_WINNT, _WIN32_IE]
Why do I get an unresolved external on main() in ATL project release builds? [#undef _ATL_MIN_CRT]
I added some source files I got from someone else and the compiler says "couldn't find precompiled header." What's up? [#include "stdafx.h" or disable use of PCHs as appropriate]
Thanks. Now, what's a PCH?
What does a debug assert failed mean? [you have a bug]
How do I change the background color of a dialog, or draw a picture as the background? [WM_ERASEBKGND]
How do I change the cursor when it's in my window? [WM_SETCURSOR]
How do I show/hide a window? [ShowWindow()]
How do I enable/disable a dialog control (button, etc)? [EnableWindow()]
In my MFC app, why doesn't EnableMenuItem() have any effect? [Use ON_UPDATE_COMMAND_UI instead]
Why can't I use a member function as a callback? [Make it static, or use a global function and pass it this, then call pThis->MemberFunc()]
I'm trying to use cout and cin, but the compiler gives an undeclared identifier error. What's up? [std::cout or using namespace std]

--Mike--
http://home.inreach.com/mdunn/
"Holding the away team at bay with a non-functioning phaser was an act of unmitigated gall. I admire gall."
-- Lt. Cmdr. Worf

memset with 32 bit values

Alex Griffing30-Jun-01 11:09

Re: memset with 32 bit values

30-Jun-01 11:09

Hi All!
If I have, for example, the bits of a DIBSection and I want to set it to a given (32 bit) color, I could say:

(1)
for (int i=0; i<nPixels; i++) pbits[i] = mycolor;

or:

(2)
__int32 *p=pbits;
while (p<pbits+nPixels) *p++ = mycolor;

but if I wanted to set it to black (or a similar color where the components are all the same) then I could just say:

(3)
memset(pbits, 0, nPixels*4);

So I guess I'm wondering if there's a way to replace (1) and (2) by a built-in function that I don't know about but which looks something like:

memset_32_at_a_time(pbits, mycolor, nPixels);

(and which would presumably be faster than either of the first two methods)
Thanks for any help with this!

Mike Nordell30-Jun-01 11:35

Mike Nordell

30-Jun-01 11:35

You might use std::fill or std::fill_n. There are no C runtime library functions for this.

Re: memset with 32 bit values

Ben Burnett30-Jun-01 13:17

Ben Burnett

30-Jun-01 13:17

Alex,

memset does almost exactly what you do in your second function (unless you using an Alpha or PowerPC chip set, which calls RtlFillMemory). You could use memcpy in a loop, but I doubt it would give you any enhancements in speed.

-Ben

---------
On the topic of code with no error handling -- It's not poor coding, it's "optimistic" Wink | ;)

Re: memset with 32 bit values

Alex Griffing30-Jun-01 14:07