C / C++ / MFC Discussion Boards

bpChristoph30-Jan-04 4:05

30-Jan-04 4:05

the windows explorer can view files as thumbnails. i have image files with my very special format, and i would like that the explorer shows also thumbnails for this files. how does this work? atl? com? ...

What is the diff between ?Foo@Class and ?FooA@Class in DLL export?

vmaltsev30-Jan-04 3:14

vmaltsev

30-Jan-04 3:14

Hi everyone,

I have a DLL with some classes in it. Header file have dllexport feature on class.
This class has some methods, several of them are virtual.
So, the problem is that my test app looking for Foo method in DLL, but can't find it because in DLL it's defined as FooA, but not Foo.
Can somebody tell me what's wrong?
In this [post^] I describe situation in detailes with some code examples.

Thanks in advance,
va'Lery.

Re: What is the diff between ?Foo@Class and ?FooA@Class in DLL export?

Joel Lucsy30-Jan-04 3:23

Joel Lucsy

30-Jan-04 3:23

I'm not positive on this, but I believe the A specifies that the function is cdecl. I'd double-check the calling conventions.

--
Joel Lucsy

Re: What is the diff between ?Foo@Class and ?FooA@Class in DLL export?

vmaltsev30-Jan-04 3:53

vmaltsev

30-Jan-04 3:53

Thanks for an idea.

I tried all three possible conventions, but result is still the same.
So that's not it.

va'Lery

Re: What is the diff between ?Foo@Class and ?FooA@Class in DLL export?

Mike Dimmick30-Jan-04 4:56

Mike Dimmick

30-Jan-04 4:56

I suspect that in the DLL, the function has the same name as a Windows function whose header you have included, while you haven't included the same header in the application.

Example: the Windows header WinBase.h defines the functions DeleteFileA and DeleteFileW. It also maps the name DeleteFile via a macro to DeleteFileA or DeleteFileW depending on whether the UNICODE symbol is defined. This allows you to switch between using the ANSI and Unicode versions of the functions simply by defining or undefining UNICODE.

Unfortunately the macro processor has no idea of scope and doesn't realise that you actually wanted to refer to a class member function rather than to refer to the Windows function, so it replaces your Foo with FooA.

Solutions: either rename the function, or #undef the macro. If you #undef the macro, consider using #pragma push_macro and #pragma pop_macro to store and retrieve the macro value (supported in VC 6.0, even though undocumented).

Using #undef in this way is a real hassle, though, so I'd simply rename the offending function.

Re: What is the diff between ?Foo@Class and ?FooA@Class in DLL export?

vmaltsev30-Jan-04 5:10

vmaltsev

30-Jan-04 5:10

That's it!
You're absolutely right. Smile | :)

Thanks a lot!

Re: What is the diff between ?Foo@Class and ?FooA@Class in DLL export?

Mukkie30-Jan-04 23:49

Mukkie

30-Jan-04 23:49

Hello!

use UndName.Exe and pass full decorated function name to see it's full undecorated name.

Smile | :)

PASSTHROUGH printing using Escape

Jimmy M Joy30-Jan-04 3:10

Jimmy M Joy

30-Jan-04 3:10

//......... struct for passing info to Escape........
struct Buff
{
DWORD BufLength;
char str[256];
};
//..............This is the code snippet................

char* outPut=(char*)malloc(sizeof(char)*256);
CString sControlCode;

CDC cdc;
cdc.CreateDC(NULL, m_cmbPrinters, NULL, NULL);

DOCINFO di;
::ZeroMemory(&di, sizeof(DOCINFO));
di.cbSize = sizeof(DOCINFO);
di.lpszDocName = "My Doc";

cdc.StartDoc(&di);
cdc.StartPage();
sControlCode.Format("%x%x",27,'E');
cdc.TextOut(12,34,"Hello Test Out here .... ");

Buff b;
int index=0;
char *p=sControlCode.GetBuffer(256);;

while(*p!='\0')
{
b.str[index++]=*p;
p++;
}

b.str[index++]='\0';

b.BufLength = sControlCode.GetLength();
int s=PASSTHROUGH;
if(cdc.Escape( QUERYESCSUPPORT, sizeof(int) , (const char*)&s , strlen(outPut) , outPut ))
{
cdc.Escape( PASSTHROUGH, 0 , (LPCSTR) &b , strlen(outPut) , outPut );
}
cdc.TextOut( 0, 150, "PASSTHROUGH Escape Function" );

cdc.EndPage();
cdc.EndDoc();
cdc.DeleteDC();

//..................
The printer code "ESC E" for the Epson LX 1050+ enables emphasized printing.
When i use the WritePrinter Api i pass the printer code as '\x1b\x45' and it works fine.The next line gets printed in bold.The WritePrinter Api needs handle to printer device but i need to do the printing through the device context.So the only way to pass printer code is via Escape.But when i pass the string via "Escape" the printer doesn't see it as a command,it just sees it as some non-printable character.So,how do i give printer commands via escape.Please,can someone help me out?

Re: PASSTHROUGH printing using Escape

basementman30-Jan-04 9:56

basementman

30-Jan-04 9:56

I suspect that your buffer b does not contain the two bytes of value x1B and E. Try hardcoding the Escape call to pass "\x1BE" and a length of 2.

EX: cdc.Escape(PASSTHROUGH,2,"\x1BE",NULL);

onwards and upwards...

Re: PASSTHROUGH printing using Escape

Jimmy M Joy30-Jan-04 17:29

Jimmy M Joy

30-Jan-04 17:29

I tried this code.

EX: cdc.Escape(PASSTHROUGH,2,"\x1BE",NULL);

But i'm getting the following compile time error.

: error C2022: '446' : too big for character.

i tried this code in this manner also.

EX: cdc.Escape(PASSTHROUGH,2,"\x1B\x45",NULL);

now the complie time error gone but it's gives a "memory could not be read" run time error.

Hope you will be able to nail it down.

Re: PASSTHROUGH printing using Escape

basementman2-Feb-04 4:13

basementman

2-Feb-04 4:13

Are you compiling with unicode?

onwards and upwards...

template class friend of another template class

Jerome Conus30-Jan-04 2:36

Jerome Conus

30-Jan-04 2:36

Hi !

I'd like to know if it's possible to have a template class being friend of another template class to access it's private members.

For example, I'd like the class CTreeNode<T> to be friend of CTree<T>.

I tried several syntaxes :

friend class CTree;

friend class CTree<T>

but it didn't work and I cannot think of another syntax.

How can I do this ?

Thanks !
Jerome

Re: template class friend of another template class

toxcct30-Jan-04 3:11

toxcct

30-Jan-04 3:11

if parameter T is the same in both case, typing that would be good :

<font style="color:blue">template class</font> CTree<<font style="color:blue">typename</font> T> {
    <font style="color:green">//private members...</font>
<font style="color:blue">public</font>:
    <font style="color:green">//...</font>
    <font style="color:blue">friend class</font> CtreeNode<T>;
};

TOXCCT alias Nicolas C.

Right click menu and sending messages

lobanovski30-Jan-04 2:09

lobanovski

30-Jan-04 2:09

hi all,

i'm ashamed to ask such questions, but i can't even figure it out how i can form a query to search for this on the web site or the internet...

1. i need to mimic standard menu items from user-defined ones... let me explain, MFC - standard MDI app (made by the wizard) has few standard menu items (File->Open... for example). Now i made a dilog, which has a button in it, and if the user clcks that button, the handler must act like it's a standard CDocument::OnOpenDocument(...) method. I know, I can construct CFileDialog myself, show it to the user and call CMyDoc::OnOpenDocument(string)... but this will defeat Doc-View approach... What can i do? Just send the message ID_FILE_OPEN... to what window than??

2. right button click and a popup menu appears. what's it name? where can read more about it?

thanks for your time!
alex

debug - is my life style

Re: Right click menu and sending messages

Michael P Butler30-Jan-04 3:39

Michael P Butler

30-Jan-04 3:39

lobanovski wrote:
2. right button click and a popup menu appears. what's it name? where can read more about it?

It is called a "context menu". MSDN and CodeProject have information on them.

Michael

But you know when the truth is told,
That you can get what you want or you can just get old,
Your're going to kick off before you even get halfway through.
When will you realise... Vienna waits for you? - "The Stranger," Billy Joel

template magic - generic callbacks + return values

peterchen30-Jan-04 0:16

peterchen

30-Jan-04 0:16

I'm trying to design some generic callbacks, which works well enough (using similar techniques to Andrescu's ScopeGuards[^]), except for the return value of the callback function.

for void, it#s simple:

struct CCallback { virtual void Call() = 0; }

template <class T>
struct CCallbackFunc_0 : public CCallback
{
   T func;
   CCallbackFunc_0(T func_) : func(func_) {}
   void Call() { func(); }
};

template <class T>
CCallback * CreateCallback(T func_)
{
  return new CCallbackFunc_0<T>(func_);
}

Now I figure I could have two separate branches, one templatized over the return type, but this makes a lot of code, and breaks the nice syntax for using CreateCallback.

Any ideas? Suggestions? Other approaches?

Flirt harder, I'm a coder.

mlog || Agile Programming | doxygen

Re: template magic - generic callbacks + return values

Ryan Binns30-Jan-04 2:23

Ryan Binns

30-Jan-04 2:23

Have you tried using a template, specifying void as the return type? The compiler will spit out a warning (not an error) if a void function returns a value, which you can safely ignore.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: template magic - generic callbacks + return values

peterchen30-Jan-04 3:00

peterchen

30-Jan-04 3:00

I'd like to be able to receive the return value when I do the "Call" through the base class (hence the idea of templating the base class over return type)

Flirt harder, I'm a coder.

mlog || Agile Programming | doxygen

Communicating with Proxy

sinuommen29-Jan-04 22:32

sinuommen

29-Jan-04 22:32

i would like to build an application to communicate with the Proxy. hw to do it

Thank You

Re: Communicating with Proxy

Prakash Nadar29-Jan-04 23:11

Prakash Nadar

29-Jan-04 23:11

I cant give you direct solution, but can give you pointers.

you need to know which proxy you are targeting,
HTTP 1/1 proxy, or sock, etc
mostly it is HTTP 1/1 proxy, so if you could refer the RFC for HTTP you will know how to do it.
regards,
Prakash.

Toughest Steel Comes From Hottest Furnance

a RSS reader

Jerome Conus29-Jan-04 20:46

Jerome Conus

29-Jan-04 20:46

Hi !

I'd like to try to write a very simple RSS reader, but...well, I have no idea where to start.
I've seen that I would need to read an XML file at a specific internet address and parse this XML file, but I'm wondering how other readers work : do I have to poll every x minutes the RSS feed and check for new informations or is there a way to get informed when new info is available ?

Thanks for your help !
Jerome

Re: a RSS reader

Taka Muraoka29-Jan-04 21:43

Taka Muraoka

29-Jan-04 21:43

Jerome Conus wrote:
do I have to poll every x minutes the RSS feed and check for new informations or is there a way to get informed when new info is available

He he. Welcome to the wonderful world of RSS. You've just found one of the many cans of worms that litter this particular landscape. RSS 2.0 has a way of notifying clients when things have changed but nobody bothers with it.

RSS Bandit[^] is open source so that should get you started.

Awasu is, of course, way cooler but I'm not giving away any source Smile | :)

Lets be honest, isn't it amazing how many truly stupid people you meet during the course of the day. Carry around a pad and pencil, you'll have twenty or thirty names by the end of the day - George Carlin

Awasu 1.2 [^]: A free RSS reader with support for Code Project.

URGENT : Black Image???

chio110229-Jan-04 20:16

chio1102

29-Jan-04 20:16

I am trying to interface my C code converted from Matlab with OpenCV.
I tried to get OpenCV to display the image I got from the Matlab
converted C code, but I got a BLACK IMAGE.

- FG is of mxArray * type.
- Using mxGetPr(FG) is supposed to return me the pointer to first
element of FG.
- Then I tried to capture the data in FG in char_ptr.
- And pass in the data in char_ptr into oImage->imageData.
- But all I get is a black image.
- Below is my program:

Can anyone please tell me what is wrong? Sigh | :sigh:

/*assigning the ouput from Matlab converted code to FG*/
mlfAssign(&FG, mlfIndexRef(mclVv(class0, "class"), ".FG"));
int m = mxGetM( FG );
int n = mxGetN( FG );
double * double_ptr = 0;
char char_ptr[240][320];
int i, j, count = 0;

double_ptr = mxGetPr( FG );
for(j=0;j<n;j++){
for(i=0;i<m;i++){
char_ptr[i][j]=(char)(*(double_ptr+count));
}
count++;
}
oimage =="" cvcreateimage(="" cvsize(n,="" m="" ),="" ipl_depth_8u,="" 1="" );
oimage-="">imageData = *char_ptr;
cvSaveImage("outputFG.jpg", oImage);

Please help...

pistachio

i want to get the handle of Dialog , that i created after clicking on a button

Anonymous29-Jan-04 20:10

Anonymous

29-Jan-04 20:10

HI,

i m begginer.
I want to get the handle of a Dialog , that i created after cliking on a button . (for both .. Modless and model)

plz tell me.

thanx

Re: i want to get the handle of Dialog , that i created after clicking on a button

SJolly29-Jan-04 22:03

SJolly

29-Jan-04 22:03

Hello,

The handle is a member of the CDialog object - m_hWnd.

I think this will be NULL until you have called the Create function on a modeless window.

Regards,
Simon

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