C / C++ / MFC

Re: cross platform tcp c program

15-Apr-15 21:40

You write it by coding according to the rules that apply for each platform.

Albert Holguin16-Apr-15 8:25

Albert Holguin

16-Apr-15 8:25

Sockets aren't exactly implemented the same way across multiple platforms. To achieve a cross-platform program that uses sockets, you can either use compile time switches (#defines) to use the appropriate platform-specific calls and system libraries or use a third party library that already has this compile time switching internally.

A few cross-platform socket libraries:
0) http://zeromq.org/[^]
1) www.boost.org (asio library)[^]
2) Larger frameworks have this too (Qt[^], wxWidgets[^])

CAsyncSockets Blocking/Non blockung

ForNow15-Apr-15 15:41

ForNow

15-Apr-15 15:41

Hi
I am somewhat new to TCP/IP, I have been doing some reading on blocking vs non blocking sockets. So my question is when creating a CAsyncsocket object is constructed and created is there a option for what type of socket
Secondly when you get a notification from one of the callback on receive onsend etc
With an error say WSAEINPROGRESS
From the call backs I guess you should just return

Re: CAsyncSockets Blocking/Non blockung

Richard MacCutchan15-Apr-15 21:39

Re: CAsyncSockets Blocking/Non blockung

15-Apr-15 21:39

See https://msdn.microsoft.com/en-us/library/1s9cycf8.aspx[^] for socket options.

ForNow16-Apr-15 10:38

ForNow

16-Apr-15 10:38

Thanks I see there are also some other options with ioctl

Initialisation of a Structure, Can anyone see the Obvious?

Bram van Kampen15-Apr-15 14:59

Bram van Kampen

15-Apr-15 14:59

Hi,

I have the following Code:

C++

</#include "stdafx.h"

struct DB_FIELD{
    const char* FieldName;
    const char* DesignerComments;
    const unsigned int FieldFlags;

    const int FieldType;
    const int FieldEltSize;
    const int FieldEltCount;
    const int FieldOffset;
    const unsigned char PaddingChar;
};

struct DB_FIELD TestFieldItem={
    "Key",  // FieldName
    NULL,   // DesignerComment
    0X00000000, // Field Flags
    13,     // Field Type
    8,  // Field Elt Size
    1,   //Field Elt Count
    0,   // Field Offset
    0    //Padding Char
};

This refuses to compile with the following error message:
"error C2552: 'TestFieldItem' : non-aggregates cannot be initialized with initializer list".

I must be doing something stupid, that I cannot see. Initialising Static Structures is the Cut and Trust of CPP!
Can anyone see the Obvious?

Smile | :)

Bram van Kampen

Re: Initialisation of a Structure, Can anyone see the Obvious?

Richard MacCutchan15-Apr-15 21:37

Re: Initialisation of a Structure, Can anyone see the Obvious?

15-Apr-15 21:37

I just tried that and it compiled fine. Maybe there is something more that you are not showing us.

Bram van Kampen26-Apr-15 14:39

Bram van Kampen

26-Apr-15 14:39

No, Not much more to show, just an Old Compiler!
It Cannot handle these things, but I found a workaround.
Was frightening at the time!

Thanks, Smile | :)

Bram van Kampen

Re: Initialisation of a Structure, Can anyone see the Obvious?

bling17-Apr-15 9:49

bling

17-Apr-15 9:49

As a side note, why declare each member as const?

You could instead write ...

C++

const struct DB_FIELD TestFieldItem =
{
    "Key",  // FieldName
    NULL,   // DesignerComment
    0X00000000, // Field Flags
    13,     // Field Type
    8,  // Field Elt Size
    1,   //Field Elt Count
    0,   // Field Offset
    0    //Padding Char
};

Re: Initialisation of a Structure, Can anyone see the Obvious?

Bram van Kampen26-Apr-15 14:31

Bram van Kampen

26-Apr-15 14:31

Point taken, and since discovered.

There seems to be a C(PP) language ambiguity here, relating to aggregates. There is never a problem with:

C++

const int Var=512;

Thanks for your reply,

Smile | :)

Bram van Kampen

Build errors !

Member 935023715-Apr-15 3:01

Member 9350237

15-Apr-15 3:01

Hi Guys!,

I have been working on Finite state machine based on a well documented tutorial in code project

Generic Finite State Machine (FSM)[^]

I tried compiling the sample project available with this but can't proceed because of few errors. The project is develped with VS 2010 but I'm using 2012.

I'll give the code excerpt where the error points..

C++

struct StateHandlerBase
    {
        SharedData data;
        States state;
        Transitions *m_interfaces[static_cast<size_t>(Size)];
        StateHandlerBase()
            : data(SharedData()),
            state(static_cast<States>(InitState))/*, m_interfaces({0})*/
        {
        }

    };

    typedef int DummyExplicitSpecialization;
    template <States stateParam, class Dummy=DummyExplicitSpecialization>
    struct StateHandler
        : StateHandler<static_cast<States>(static_cast<size_t>(stateParam)-1)>
    {
        TransitionImplement<StateMachineComponents, static_cast<States>(stateParam)> m_interface;
        StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)
        {
            StateHandlerBase::m_interfaces[static_cast<size_t>(stateParam)] = &m_interface;
        }
    };

    template <class DummyExplicitSpecialization>
    struct StateHandler<static_cast<States>(0), DummyExplicitSpecialization>
        : StateHandlerBase
    {
        TransitionImplement<StateMachineComponents, static_cast<States>(0)> m_interface;
        StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)
        {
            StateHandlerBase::m_interfaces[0] = &m_interface;
        }
    };

    typedef StateHandler<static_cast<States>(TerminateState), DummyExplicitSpecialization> StateHanlderType;

 StateHanlderType StateHanlderInstance;

These are the errors:

error C2976: 'Fsm<statemachinecomponents>::StateHandler' : too few template arguments

error C3855: 'Fsm<statemachinecomponents>::StateHandler': template parameter 'stateParam' is incompatible with the declaration

I'm totally stuck!!. I have no idea what is happening
Greatly appreciate possible suggestions to get out of this

David Crow15-Apr-15 3:06

15-Apr-15 3:06

Member 9350237 wrote:
Greatly appreciate possible suggestions to get out of this

How about showing the line(s) that the compiler is complaining about.

Member 935023715-Apr-15 3:16

Member 9350237

15-Apr-15 3:16

Well, It's 4th line from last.

C++

struct StateHandlerBase
    {
        SharedData data;
        States state;
        Transitions *m_interfaces[static_cast<size_t>(Size)];
        StateHandlerBase()
            : data(SharedData()),
            state(static_cast<States>(InitState))/*, m_interfaces({0})*/
        {
        }

<pre>
};

typedef int DummyExplicitSpecialization;
template &lt;States stateParam, class Dummy=DummyExplicitSpecialization&gt;
struct StateHandler
    : StateHandler&lt;static_cast&lt;States&gt;(static_cast&lt;size_t&gt;(stateParam)-1)&gt;
{
    TransitionImplement&lt;StateMachineComponents, static_cast&lt;States&gt;(stateParam)&gt; m_interface;
    StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)
    {
        StateHandlerBase::m_interfaces[static_cast&lt;size_t&gt;(stateParam)] = &amp;m_interface;
    }
};

template &lt;class DummyExplicitSpecialization&gt;
struct StateHandler&lt;static_cast&lt;States&gt;(0), DummyExplicitSpecialization&gt;
    : StateHandlerBase
{
    TransitionImplement&lt;StateMachineComponents, static_cast&lt;States&gt;(0)&gt; m_interface;
    StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)
    {
        StateHandlerBase::m_interfaces[0] = &amp;m_interface;
    }

It's here---> };

typedef StateHandler<static_cast<States>(TerminateState), DummyExplicitSpecialization> StateHanlderType;

StateHanlderType StateHanlderInstance;

Richard Andrew x6415-Apr-15 5:48

Richard Andrew x64

15-Apr-15 5:48

Member 9350237 wrote:
StateHandlerBase::m_interfaces[static_cast<size_t>(stateParam)] = &m_interface;

~~Do you mean to have that m_interface; at the end of the line?~~

Never mind. The HTML got in the way of what I was looking at.

The difficult we do right away...
...the impossible takes slightly longer.

Member 935023715-Apr-15 6:04

Member 9350237

15-Apr-15 6:04

Sorry I think the format got changed.

Basically compiler pointing at forth line from last

end of this structure

C++

struct StateHandler<static_cast<States>(0), DummyExplicitSpecialization>
        : StateHandlerBase

C++

struct StateHandlerBase
    {
        SharedData data;
        States state;
        Transitions *m_interfaces[static_cast<size_t>(Size)];
        StateHandlerBase()
            : data(SharedData()),
            state(static_cast<States>(InitState))/*, m_interfaces({0})*/
        {
        }

    };

    typedef int DummyExplicitSpecialization;
    template <States stateParam, class Dummy=DummyExplicitSpecialization>
    struct StateHandler
        : StateHandler<static_cast<States>(static_cast<size_t>(stateParam)-1)>
    {
        TransitionImplement<StateMachineComponents, static_cast<States>(stateParam)> m_interface;
        StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)
        {
            StateHandlerBase::m_interfaces[static_cast<size_t>(stateParam)] = &m_interface;
        }
    };

    template <class DummyExplicitSpecialization>
    struct StateHandler<static_cast<States>(0), DummyExplicitSpecialization>
        : StateHandlerBase
    {
        TransitionImplement<StateMachineComponents, static_cast<States>(0)> m_interface;
        StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)
        {
            StateHandlerBase::m_interfaces[0] = &m_interface;
        }
    };

    typedef StateHandler<static_cast<States>(TerminateState), DummyExplicitSpecialization> StateHanlderType;
 StateHanlderType StateHanlderInstance;

David Crow15-Apr-15 6:54

15-Apr-15 6:54

have you tried commenting out the typedefs and structs to see which one is "bugging" the compiler? That might help to narrow it down.

David Crow15-Apr-15 6:51

15-Apr-15 6:51

Member 9350237 wrote:
Well, It's 4th line from last.

Depending on what you are considering a line, the fourth line from the last is:

StateHandler() : m_interface(StateHandlerBase::state, StateHandlerBase::data)

Member 9350237 wrote:
It's here---> };

Not sure which }; instance you are referring to, but I do see a misplaced <pre> tag. Why is that there?

Brisingr Aerowing15-Apr-15 11:22

Brisingr Aerowing

15-Apr-15 11:22

A glitch in the Matrix.

(Markdown bug)

What do you get when you cross a joke with a rhetorical question?

The metaphorical solid rear-end expulsions have impacted the metaphorical motorized bladed rotating air movement mechanism.

Do questions with multiple question marks annoy you???

Richard MacCutchan15-Apr-15 7:19

MFC: flickering issue with GDI+

15-Apr-15 7:19

You should really use the forum at the end of the article, so the person who wrote the code can help you.

Member 1128851411-Apr-15 20:27

Member 11288514

11-Apr-15 20:27

I create a sample dialog application which has a circle drawn. Also on mouse move the circle will be re-drawn. I am providing my code below. Its also compilable.

I tried using double buffering and erasebackground, i was not getting the flickering issue, but i observed that the drawining is not erased properly. So to erase, in OnPaint i wrote the erasing code. Again i am facing the flickering issue.

CPaintDC dc(this);
GetClientRect(&clientRect);

circle = clientRect;
circle.DeflateRect(100,100);
dc.SelectStockObject(NULL_BRUSH);
dc.SelectStockObject(NULL_PEN);
dc.FillSolidRect(circle, ::GetSysColor(COLOR_BTNFACE));

Bitmap buffer(circle.right, circle.bottom);
Graphics graphicsbuf(&buffer);
Graphics graphics(dc.m_hDC);
graphicsbuf.SetSmoothingMode(SmoothingModeHighQuality);

SolidBrush brush(Color(255,71,71,71));
Pen bluePen(Color(255, 0, 0, 255),1);

graphicsbuf.DrawEllipse(&bluePen,Rect(circle.left,circle.top,circle.Width(),circle.Height()));
graphicsbuf.SetSmoothingMode(SmoothingModeHighQuality);
graphics.DrawImage(&buffer, 0, 0);

}

void CPOCDlg::OnMouseMove(UINT nFlags, CPoint point)
{
m_point = point;
InvalidateRect(circle,FALSE);

CDialogEx::OnMouseMove(nFlags, point);

}

BOOL CPOCDlg::OnEraseBkgnd(CDC* pDC)
{
return TRUE;
}
Please let me know if i am doing any mistake.

Re: MFC: flickering issue with GDI+

David Crow12-Apr-15 16:55