EXPERT help URGENTLY NEEDED on InterOp (Managed C++?) issue

[E.T. Grey]

Hi,

I have a C++ DLL that I want to use from a C# project. I am actually
usng a lot of advanced C++ features like templates, partial/specialized
templates, functors and callbacks. I am also using STL containers like
std::string, std::vector and std::map quite extensively in my C++ DLL API.

However, I can simplify the API so as to make it easier to use from C#.
Below, is a very simple "proof of concept" C++ DLL. I would be extremely
grateful if someone could show me how I can use this Dll from C#:

Here is the code:

/* C++ code (Header)
(trivial proof of concept DLL */

#ifdef TESTDLL_EXPORTS
#define CCONV __declspec(dlle xport)
#else
#define CCONV __declspec(dlli mport)
#endif

typedef enum {
ONE ,
TWO ,
THREE
} myEnum;

typedef struct mystruct_ {
int x ;
float y ;
char z[8] ;
} myStruct ;

typedef int (*INT_FPTR)(con st char*, const MyStruct*) ;

class CCONV MyClass {
public:
MyClass();
MyClass(const MyClass&);
MyClass& operator = (const MyClass&);
~MyClass();

private:
//some private variables here ..
};

class CCONV DClass : public MyClass {
public :
DClass();
DClass(const DClass&);
DClass& operator = (const DClass&);
~DClass();

const char* foo(void);
int barney(int, myEnum, const myStruct*); //throws an exception
void register_callba ck( INT_FPTR ) ;

private:
INT_FPTR cb ;
};
Many Thanks

[Jeff Louie]

ET I am no expert, but VS2005 managed C++ supports templates and the STL
while emitting MSIL.

Regards,
Jeff

*** Sent via Developersdex http://www.developersdex.com ***

[Willy Denoyette [MVP]]

"E.T. Grey" <ne****@alpha-centauri.com> wrote in message
news:dk******** **@nwrdmz01.dmz .ncs.ea.ibs-infra.bt.com...

Hi,

I have a C++ DLL that I want to use from a C# project. I am actually usng
a lot of advanced C++ features like templates, partial/specialized
templates, functors and callbacks. I am also using STL containers like
std::string, std::vector and std::map quite extensively in my C++ DLL API.

However, I can simplify the API so as to make it easier to use from C#.
Below, is a very simple "proof of concept" C++ DLL. I would be extremely
grateful if someone could show me how I can use this Dll from C#:

Here is the code:

/* C++ code (Header)
(trivial proof of concept DLL */

#ifdef TESTDLL_EXPORTS
#define CCONV __declspec(dlle xport)
#else
#define CCONV __declspec(dlli mport)
#endif

typedef enum {
ONE ,
TWO ,
THREE
} myEnum;

typedef struct mystruct_ {
int x ;
float y ;
char z[8] ;
} myStruct ;

typedef int (*INT_FPTR)(con st char*, const MyStruct*) ;

class CCONV MyClass {
public:
MyClass();
MyClass(const MyClass&);
MyClass& operator = (const MyClass&);
~MyClass();

private:
//some private variables here ..
};

class CCONV DClass : public MyClass {
public :
DClass();
DClass(const DClass&);
DClass& operator = (const DClass&);
~DClass();

const char* foo(void);
int barney(int, myEnum, const myStruct*); //throws an exception
void register_callba ck( INT_FPTR ) ;

private:
INT_FPTR cb ;
};
Many Thanks

What do you mean by throws an exception?, "barney" is a C++ member function,
you can't create instances of native C++ classes from C#, so you can't call
member functions.
Your only options are:
1. create a managed C++ class in a managed assembly (using vs2005 C++/CLI)
that wrap your unmanaged C++ class(es).
2. convert your public interfaces (exposed to C#) to managed C++ classes and
compile with C++/CLI (vs2005).

Willy.

[E.T. Grey]

Willy Denoyette [MVP] wrote:

"E.T. Grey" <ne****@alpha-centauri.com> wrote in message
news:dk******** **@nwrdmz01.dmz .ncs.ea.ibs-infra.bt.com...

Hi,

I have a C++ DLL that I want to use from a C# project. I am actually usng
a lot of advanced C++ features like templates, partial/specialized
templates, functors and callbacks. I am also using STL containers like
std::string , std::vector and std::map quite extensively in my C++ DLL API.

However, I can simplify the API so as to make it easier to use from C#.
Below, is a very simple "proof of concept" C++ DLL. I would be extremely
grateful if someone could show me how I can use this Dll from C#:

Here is the code:

/* C++ code (Header)
(trivial proof of concept DLL */

#ifdef TESTDLL_EXPORTS
#define CCONV __declspec(dlle xport)
#else
#define CCONV __declspec(dlli mport)
#endif

typedef enum {
ONE ,
TWO ,
THREE
} myEnum;

typedef struct mystruct_ {
int x ;
float y ;
char z[8] ;
} myStruct ;

typedef int (*INT_FPTR)(con st char*, const MyStruct*) ;

class CCONV MyClass {
public:
MyClass();
MyClass(con st MyClass&);
MyClass& operator = (const MyClass&);
~MyClass();

private:
//some private variables here ..
};

class CCONV DClass : public MyClass {
public :
DClass();
DClass(cons t DClass&);
DClass& operator = (const DClass&);
~DClass();

const char* foo(void);
int barney(int, myEnum, const myStruct*); //throws an exception
void register_callba ck( INT_FPTR ) ;

private:
INT_FPTR cb ;
};
Many Thanks
What do you mean by throws an exception?, "barney" is a C++ member function,

What is so difficult to understand by this statement?. C++ methods *can*
throw exceptions - maybe managed C++/C# (or should that be C dumb)
classes can't ?
you can't create instances of native C++ classes from C#, so you can't call
member functions.
Your only options are:
1. create a managed C++ class in a managed assembly (using vs2005 C++/CLI)
that wrap your unmanaged C++ class(es).

<snip>
I already knew that. Everybody (including the MS site tells me I need to
write managed C++ wrapper classes around my C++ classes - but there is
no useful examples given anywhere - most of the examples are to do with
calling C functions from C#. So far its been all talk and no examples -
has anyone *actually* EVER called C++ classes from C#? If it can't be
done or it has never been tried out in the real world - just be man
enough to say it instad of issuing the blanket line : "write managed C++
classes around your C++ classes". No one as yet (and that included MS
itself) afaik, has actually provided an example of using C++ classes
exported from a C++ DLL - so come on : can it be done or NOT ?. If yes
(everyone tells me it can - but has no examples) - HOW the hell is it
done - does anyone actually even know?. I provided a simple no brainer
C++ DLL and expected at least some pseudocode to show how I can call the
2/3 functions from C# - apparently, no one really knows how to do this ....

[Ashura]

chill man, we r all here to help others!
while ya cudnt create instance of c++ class in c#, its a bloody truth.
HOWEVER, this NOT so hard to get around.

//remove those lines out cuz ya dont need to export the whole
//class out from a c++ class
#ifdef TESTDLL_EXPORTS
#define CCONV __declspec(dlle xport)
#else
#define CCONV __declspec(dlli mport)
#endif

NO CHANGES for ya current classes, they r workin just fine
//add the following
extern "C" __declspec(dlle xport) DClass* CreateInstance( );
extern "C" __declspec(dlle xport) DClass* DestroyInstance (DClass* obj);

//create the methods to export
extern "C" __declspec(dlle xport) DClass* CreateInstance( )
{ return new DClass(); }

extern "C" __declspec(dlle xport) DClass* DestroyInstance (DClass* obj)
{ delete obj; }

/////////////////////////////////////
After ya hav done ALL above, im pretty sure ya kno how to deal with object
instances afterwards, dont ya?

////////////////////////////////////
I just roughly put some sample above, it may not workin extactly as ya wish
but ya hav got the idea.

hope this helps

[Ashura]

1 more thing, mate
the thing im talkin about is PURELY c/c++ by itself.
im NOT sure that vs2005 introduces 'something' to 'managed c++' or not. ya
better check it out first.
BTW: to be honest, i HATE managed C++.

[E.T. Grey]

Ashura wrote:

chill man, we r all here to help others!
while ya cudnt create instance of c++ class in c#, its a bloody truth.
HOWEVER, this NOT so hard to get around.

//remove those lines out cuz ya dont need to export the whole
//class out from a c++ class
#ifdef TESTDLL_EXPORTS
#define CCONV __declspec(dlle xport)
#else
#define CCONV __declspec(dlli mport)
#endif

NO CHANGES for ya current classes, they r workin just fine
//add the following
extern "C" __declspec(dlle xport) DClass* CreateInstance( );
extern "C" __declspec(dlle xport) DClass* DestroyInstance (DClass* obj);

//create the methods to export
extern "C" __declspec(dlle xport) DClass* CreateInstance( )
{ return new DClass(); }

extern "C" __declspec(dlle xport) DClass* DestroyInstance (DClass* obj)
{ delete obj; }

/////////////////////////////////////
After ya hav done ALL above, im pretty sure ya kno how to deal with object
instances afterwards, dont ya?

////////////////////////////////////
I just roughly put some sample above, it may not workin extactly as ya wish
but ya hav got the idea.

hope this helps

Ok, now we are at least getting somewhere. However, your code (assuming
that this is the ONLY way forward) proves *precisely* what I had
suspected all along:

In order to use C++ classes in C#, you have to write a C API
(i.e.wrapper) around your C++ classes and *then* use the C API from
managed C++ - lol and lmao !!!, excuse me for my mirth - but one has to
admire MS for being such a dominat force in the industry despite the
fact that it has so many half-assed, half baked "technologi es" which are
so - erm f*@ked up and proprietary. C# appears to be nothing more than a
blatant plagiarism of Java (not to mention a few bits and pieces
"borrowed" from C and C++) and just enough proprietary crap to ensure
that it is not compatable with any of the "true" standard languages out
there.

This sucks BIG TIME !

PS: Thanks anyway Ashura - at least you tried. But this half cooked
language (if you can call it that) does not seem to have any saving graces.

[Bill Butler]

"E.T. Grey" <ne****@alpha-centauri.com> wrote in message
news:dk******** **@nwrdmz01.dmz .ncs.ea.ibs-infra.bt.com...
<snip>
dickhead ranting about how C# sucks, when he OBVIOUSLY hasn't given it a chance
</snip>
Dude,

If you want help, you might ATTEMPT to be civil!!
Obviously you wanted to hate C# from the start.

There are quite a few resources available for learning about Managed C++ wrapper classes. All you
need to do is LOOK for them!!

- There are a bunch of books available on Amazon(or your favorite bookseller)
- A simple GOOGLE query brought up a bunch of usable examples
- A search of GOOGLE Groups Brought up a bunch of good info

I just found them myself while writing this post.

Chill out dude

[Willy Denoyette [MVP]]

"E.T. Grey" <ne****@alpha-centauri.com> wrote in message
news:dk******** **@nwrdmz02.dmz .ncs.ea.ibs-infra.bt.com...

Willy Denoyette [MVP] wrote:

"E.T. Grey" <ne****@alpha-centauri.com> wrote in message
news:dk******** **@nwrdmz01.dmz .ncs.ea.ibs-infra.bt.com...

Hi,

I have a C++ DLL that I want to use from a C# project. I am actually usng
a lot of advanced C++ features like templates, partial/specialized
templates, functors and callbacks. I am also using STL containers like
std::strin g, std::vector and std::map quite extensively in my C++ DLL
API.

However, I can simplify the API so as to make it easier to use from C#.
Below, is a very simple "proof of concept" C++ DLL. I would be extremely
grateful if someone could show me how I can use this Dll from C#:

Here is the code:

/* C++ code (Header)
(trivial proof of concept DLL */

#ifdef TESTDLL_EXPORTS
#define CCONV __declspec(dlle xport)
#else
#define CCONV __declspec(dlli mport)
#endif

typedef enum {
ONE ,
TWO ,
THREE
} myEnum;

typedef struct mystruct_ {
int x ;
float y ;
char z[8] ;
} myStruct ;

typedef int (*INT_FPTR)(con st char*, const MyStruct*) ;

class CCONV MyClass {
public:
MyClass();
MyClass(cons t MyClass&);
MyClass& operator = (const MyClass&);
~MyClass() ;

private:
//some private variables here ..
};

class CCONV DClass : public MyClass {
public :
DClass();
DClass(con st DClass&);
DClass& operator = (const DClass&);
~DClass();

const char* foo(void);
int barney(int, myEnum, const myStruct*); //throws an exception
void register_callba ck( INT_FPTR ) ;

private:
INT_FPTR cb ;
};
Many Thanks
What do you mean by throws an exception?, "barney" is a C++ member
function,

What is so difficult to understand by this statement?. C++ methods *can*
throw exceptions - maybe managed C++/C# (or should that be C dumb) classes
can't ?
Difficult to understand is, what exception could possibly be thrown by
something that you are not able to call from C#.

you can't create instances of native C++ classes from C#, so you can't
call member functions.
Your only options are:
1. create a managed C++ class in a managed assembly (using vs2005
C++/CLI) that wrap your unmanaged C++ class(es).

<snip>
I already knew that. Everybody (including the MS site tells me I need to
write managed C++ wrapper classes around my C++ classes - but there is no
useful examples given anywhere - most of the examples are to do with
calling C functions from C#. So far its been all talk and no examples -
has anyone *actually* EVER called C++ classes from C#?

That's exactly what we are telling here, YOU CAN'T directly call native C++
member functions from C#.

If it can't be done or it has never been tried out in the real world - just be man enough
to say it instad of issuing the blanket line : "write managed C++ classes
around your C++ classes".
What is so difficult to understand by this statement?. Write a wrapper
class using C++/CLI, MSDN contains samples how to do it.
No one as yet (and that included MS itself) afaik, has actually provided an example of using C++ classes
exported from a C++ DLL - so come on : can it be done or NOT ?. If yes
(everyone tells me it can - but has no examples) - HOW the hell is it
done - does anyone actually even know?. I provided a simple no brainer C++
DLL and expected at least some pseudocode to show how I can call the 2/3
functions from C# - apparently, no one really knows how to do this ....

Again search the MSDN docs, it contains sample and a lot more you need to
know.

Willy.

[Willy Denoyette [MVP]]

"E.T. Grey" <ne****@alpha-centauri.com> wrote in message
news:dk******** **@nwrdmz01.dmz .ncs.ea.ibs-infra.bt.com...

Ashura wrote:

chill man, we r all here to help others!
while ya cudnt create instance of c++ class in c#, its a bloody truth.
HOWEVER, this NOT so hard to get around.

//remove those lines out cuz ya dont need to export the whole
//class out from a c++ class
#ifdef TESTDLL_EXPORTS #define CCONV __declspec(dlle xport) #else #define
CCONV __declspec(dlli mport) #endif NO CHANGES for ya current classes,
they r workin just fine
//add the following
extern "C" __declspec(dlle xport) DClass* CreateInstance( );
extern "C" __declspec(dlle xport) DClass* DestroyInstance (DClass* obj);

//create the methods to export
extern "C" __declspec(dlle xport) DClass* CreateInstance( )
{ return new DClass(); }

extern "C" __declspec(dlle xport) DClass* DestroyInstance (DClass* obj)
{ delete obj; }

/////////////////////////////////////
After ya hav done ALL above, im pretty sure ya kno how to deal with
object instances afterwards, dont ya?

////////////////////////////////////
I just roughly put some sample above, it may not workin extactly as ya
wish but ya hav got the idea.

hope this helps
Ok, now we are at least getting somewhere. However, your code (assuming
that this is the ONLY way forward) proves *precisely* what I had suspected
all along:

In order to use C++ classes in C#, you have to write a C API (i.e.wrapper)
around your C++ classes and *then* use the C API from managed C++ - lol
and lmao !!!, excuse me for my mirth - but one has to admire MS for being
such a dominat force in the industry despite the fact that it has so many
half-assed, half baked "technologi es" which are so - erm f*@ked up and
proprietary. C# appears to be nothing more than a blatant plagiarism of
Java (not to mention a few bits and pieces "borrowed" from C and C++) and
just enough proprietary crap to ensure that it is not compatable with any
of the "true" standard languages out there.

WRONG - you need to write a (managed) wrapper class using C++/CLI, what is
shown in this sample is an alternative way.
This sucks BIG TIME !

PS: Thanks anyway Ashura - at least you tried. But this half cooked
language (if you can call it that) does not seem to have any saving
graces.

Willy.