C / C++ / MFC

Re: Multithreading question The Code

13-Jan-17 3:28

Do you have an-email address I can e-mail you offline

Thanks

leon de boer14-Jan-17 22:47

leon de boer

14-Jan-17 22:47

It's on my bio

In vino veritas

Re: Multithreading question

ForNow8-Jan-17 22:56

Re: Multithreading question

8-Jan-17 22:56

thanks
The Visual Studio Thread windows I know has the ability to freeze threads

Regardless I'll download the extension

Let me explain the nature of the problem

I'll writing an a debugger for another platform (working with an emulator )

I am modifying the emulated "C" code

the way interrupt the "debugged" code/program

is by overlaying the instruction which gives me control and shows the user the code

I quickly put back the over laid instruction

this works well when the user is debugging a Single Threaded program

however in a multiThreaded programs other threads or tasks executing the same code

get a operation exception before I put the code back

The way I coded this was as soon as I overlay the instruction I do a

ResetEvent which cause a Event to be non-signaled and stop the other threads/tasks

from executing this code until I have a chance

to put back the instruction I then do a SetEvent

to let the other threads/tasks execute the code

Something is obviously not working out right in this timing

In Visual Studio I can observe how QUICKLY The Windows dispatcher

Switches from thread to thread

Thanks for your help

Munchies_Matt23-Jan-17 6:32

Munchies_Matt

23-Jan-17 6:32

If you get this then you need to use thread synchronisaiton so that WHATEVER happens, and it will, one day, your threads process data and events in a coordinated fashion.

MFC ribbon designer (gallery button)

Maximilien6-Jan-17 9:43

Maximilien

6-Jan-17 9:43

(I still must be in the spirit of Christmas)

Q: How do I add gallery buttons items to a gallery button with the resource editor ?

I created a default application with the ribbon UI.

In the resource editor, I added a "Gallery Button" and into that I added a few button items in the collection
I manually added event handlers for each item.

When I start the application, the gallery button just looks like a button and when I click on it, no "menu" is displayed.

I looked at the samples projects ( RibbonGadgets and RibbonMDI) and they just code the ribbon manually.

Q: Am I missing something? The properties for the gallery button does not show anything useful.

Q: Should I just give up on the ribbon designer and code everything manually ?

Thanks.

Max.

I'd rather be phishing!

Re: MFC ribbon designer (gallery button)

DeeEllEll30-Mar-17 4:55

DeeEllEll

30-Mar-17 4:55

Did you ever find an answer here? I have the same issue.

Is function prototyping dead?

Vaclav_6-Jan-17 5:43

Vaclav_

6-Jan-17 5:43

A semi-popular IDE compiles my C++ code without declaring function prototype.
Did I missed the newsflash or just an compiler option?
Seems odd.

Richard MacCutchan6-Jan-17 5:49

Richard MacCutchan

6-Jan-17 5:49

You only need prototypes for forward declarations. And IDEs do not do the compiling, that's the compiler's job.

Vaclav_6-Jan-17 16:19

Vaclav_

6-Jan-17 16:19

True, but I have been using IDE whose authors are very fond of their "beginners feature " which actually builds prototypes "for you". So they claim.

I am now test driving another IDE, still based on GCC and the first test function I used compiled without prototype, that is why I made this post.

Next function failed without prototype, so I am not sure what is going on.

So what is the difference between prototype and forward declaration?
Or is there a difference?

Richard MacCutchan6-Jan-17 21:55

Richard MacCutchan

6-Jan-17 21:55

When the compiler comes across a function call it checks its tables for a declared prototype. If it cannot find one then it will infer a definition from the parameters of the function call. When it then finds the actual function it will check that the definition matches the stored declaration. If it does, then all well and good. If it does not then it will throw out an error message.

As to your last question, a prototype is a forward declaration. It just tells the compiler the type of the parameters and return value of the function, so it can check on any calls made to the function before it is found in the source. The same applies to external functions whose prototypes are in .h files.

Jochen Arndt6-Jan-17 22:17

6-Jan-17 22:17

A declaration (prototype) describes an object (function, class, variable).

C++

int some_function(int some_arg);

A definition (implementation) implements an object.

C++

int some_function(int some_arg)
{
    int result = 0;
    // some code
    return result;
}

If there is no declaration for an object, the definition implies the declaration.

The compiler needs a declaration when an object is used the first time (accessing a variable, calling a function). So there is no need for a declaration if the first usage is located after the definition in the source code.

While strictly speaking all declarations are forward declarations, the term is mainly used with function declarations in header files where a pointer or reference to another class is passed as function argument. An example:

C++

// Header file for MyClass

// Forward declaration for OtherClass.
class OtherClass;

class MyClass
{
    MyClass();
    SomeFunction(OtherClass &otherClass);
};

The implementation file of MyClass must still include the header file containing the OtherClass declaration. But the above header file must not do so which reduces the compile time. More important, this must be used when both classes use the other which would normally require that both header files include each other which would lock the compiler (recursive inclusion).

See also this SO thread: c++ - What is the difference between a definition and a declaration? - Stack Overflow[^]

Vaclav_7-Jan-17 4:29

Vaclav_

7-Jan-17 4:29

The compiler needs a declaration when an object is used the first time (accessing a variable, calling a function). So there is no need for a declaration if the first usage is located after the definition in the source code.

Perfect answer - that is exactly why my test function - first one in header file - did not need declaration.

Jochen,
I really appreciate your help - always right to the point. Thanks

PS
Are you by any chance teacher / instructor ? You sure know how to explain stuff.

Cheers
Vaclav

Jochen Arndt8-Jan-17 20:58

8-Jan-17 20:58

Thank you.

I'm not a teacher. I'm an R&D engineer (hardware and software).

Jochen Arndt6-Jan-17 6:49

6-Jan-17 6:49

A function definition is also a declaration if there was none so far. The compiler (not the IDE) will add it to it's internal declaration list when processing such a function.

Multi Core question

ForNow4-Jan-17 4:11

4-Jan-17 4:11

Hi
I have C/C++ solution/project
The parent process is C the child process is MFC C++.
Each in its own project

The C project has a number of threads.

I have a quad core laptop.

Is there any way of knowing how many cores the .exe(s) is/are using. Don't know if task manager is the answer.

More so can I have an affinity of a thread to a core ?

Thanks

Jochen Arndt4-Jan-17 4:39

4-Jan-17 4:39

It is all handled by the operation system. Don't care about. While it is possible to set a thread affinity it is usually not necessary and often counterproductive.

If a process has multiple threads it will use multiple cores when available. But there is no single core assigned to a specific thread. The OS assigns the cores so that a thread runs on different cores.

ForNow4-Jan-17 4:50

4-Jan-17 4:50

Is there anything in task manager or VS debugger or maybe the Kernal debugger that would show me any information about this

Thanks

Jochen Arndt4-Jan-17 5:01

4-Jan-17 5:01

Showing information about the core that runs a specific thread makes no sense due to the fast switching between the cores.

For process information have a look at the Sysinternals Suite[^].

ForNow4-Jan-17 5:06

4-Jan-17 5:06

Thanks so much Smile | :)

Create a program

Yudha Eka Saputra3-Jan-17 18:01

Yudha Eka Saputra

3-Jan-17 18:01

I wanted to make a program like this:

A bank in Indonesia want to create a program using the order of priority. The purpose of this program is to provide the serial number to its customers. No sequence given later be called by the program so that customers who have no it can go to the teller who had been appointed.
The problem in the bank there is a priority system that puts people who have a priority, so that when the customer has priority can be called up in advance from customers who do not have a priority. Create a program using DLLC to overcome this!

Victor Nijegorodov3-Jan-17 22:04

Victor Nijegorodov

3-Jan-17 22:04

Is it a homework?

Richard MacCutchan3-Jan-17 23:26

Richard MacCutchan

3-Jan-17 23:26

Sorry, but no one here is going to do your work for you. Give it a try, and if you have a specific technical question then come back and people will try to help you.

David Crow4-Jan-17 2:57

David Crow

4-Jan-17 2:57

Okay, and?

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