Managed C++/CLI

Re: How to read a pdf file using c++

7-Mar-06 22:14

Allang Garder wrote:
using c++.

do you know this is the Managed C++ forum (for .NET framework so) ?

prrusa8-Mar-06 9:14

prrusa

8-Mar-06 9:14

How would you do it in cli? I would
be interested.

Help with this basic code

Fu Manchu7-Mar-06 13:56

Fu Manchu

7-Mar-06 13:56

hi, i am having some trouble with this basic example code, i can't figure out why i am getting an error, null reference!

please help

thanks

#include "stdafx.h"<br />
<br />
#using mscorlib.dll<br />
using namespace std; <br />
<br />
<br />
class Foo<br />
{<br />
public:<br />
 Foo();<br />
 ~Foo();<br />
void DoSomeFoo();<br />
};<br />
<br />
 // constructor<br />
Foo::Foo() <br />
  {<br />
	cout<<"Constructor called!"<<endl;<br />
  }<br />
//  // destructor<br />
Foo::~Foo() <br />
  {<br />
	cout<<"Destructor called"<<endl;<br />
  }<br />
<br />
  // some method<br />
  void Foo::DoSomeFoo()<br />
<br />
  {<br />
	  cout<<"Do something funny!"<<endl;<br />
	  cout<<"Burrrp!"<<endl;<br />
  }<br />
<br />
__gc class MFoo<br />
{	<br />
private:<br />
	Foo * _foo;<br />
public:<br />
	MFoo();<br />
	~MFoo();<br />
	void ManagedDoSomeFoo();<br />
};<br />
<br />
  // constructor<br />
MFoo::MFoo() <br />
	{<br />
	 _foo = new Foo();<br />
	}<br />
  // destructor<br />
MFoo::~MFoo()<br />
	{<br />
	 delete _foo;<br />
	}<br />
<br />
  // method<br />
void MFoo::ManagedDoSomeFoo() <br />
  {<br />
	  _foo->DoSomeFoo();<br />
  }<br />
<br />
<br />
int _tmain() <br />
{ <br />
<br />
<br />
	MFoo*myfoo;<br />
	myfoo->ManagedDoSomeFoo();<br />
<br />
    return 0; <br />
}

Re: Help with this basic code

toxcct7-Mar-06 21:45

Re: Help with this basic code

7-Mar-06 21:45

where in the code are you getting this error, and what does the error message say ?
does it happen at runtime or before ?

Gavin Taylor7-Mar-06 23:39

Gavin Taylor

7-Mar-06 23:39

Your never actually creating an instance of myfoo, try changing your _tmain to:

int _tmain() 
{ 
	MFoo*myfoo = new MFoo( ); // Create an instance of this object
	myfoo->ManagedDoSomeFoo();
	return 0; 
}

Gavin Taylor
w: http://www.gavspace.com

-- modified at 5:39 Wednesday 8th March, 2006

Re: Help with this basic code

Fu Manchu8-Mar-06 12:01

Fu Manchu

8-Mar-06 12:01

thanks guys, i thought it was something like that,but i mainly use vb.net so i get a little stuck with c++.

i have been trying to wrap this example, so i can practice for a much bigger program.

i have never done this before and the help on the net is a little vague, i need a very very basic walkthrough, because the ones i have found won't compile, and its hard enough trying to debug code that you dont really understand.

i know this much....

i have a class library(.net) called fooManaged and its automatical created fooManaged.h. and i created UnManaged.h

in the UnManaged.h file i have this code.....

#include iostream <br />
 #include vcclr.h<br />
using namespace std;<br />
<br />
class Foo<br />
{<br />
public:<br />
 Foo();<br />
 ~Foo();<br />
void DoSomeFoo();<br />
};<br />
<br />
 // constructor<br />
Foo::Foo() <br />
  {<br />
	cout<<"Constructor called!"<<endl;<br />
  }<br />
//  // destructor<br />
Foo::~Foo() <br />
  {<br />
	cout<<"Destructor called"<<endl;<br />
  }<br />
<br />
  // some method<br />
  void Foo::DoSomeFoo(void)<br />
<br />
  {<br />
	  cout<<"Do something funny!"<<endl;<br />
	  cout<<"Burrrp!"<<endl;<br />
  }

in fooManaged.h i have this code....

// fooManaged.h<br />
<br />
#pragma once<br />
using namespace System;<br />
<br />
namespace fooManaged<br />
{<br />
	public __gc class MFoo<br />
{	<br />
private:<br />
	Foo * _foo;<br />
public:<br />
	MFoo();<br />
	~MFoo();<br />
	void ManagedDoSomeFoo();<br />
};<br />
  // constructor<br />
MFoo::MFoo() <br />
	{<br />
	 _foo = new Foo();<br />
	}<br />
  // destructor<br />
MFoo::~MFoo()<br />
	{<br />
	 delete _foo;<br />
	}<br />
<br />
  // method<br />
void MFoo::ManagedDoSomeFoo() <br />
  {<br />
	  _foo->DoSomeFoo();<br />
  }<br />
<br />
}

the fooManaged.cpp file just has...

#include "stdafx.h"
#include "Unmanagedfoo.h"
#include "fooManaged.h"
#using mscorlib.dll

it all compiles...but there is a big linking error!!

Compiling...
fooManaged.cpp
Linking...
LINK : error LNK2020: unresolved token (0A000005) _CxxThrowException
LINK : error LNK2020: unresolved token (0A000019) free
LINK : error LNK2020: unresolved token (0A00001A) strlen
LINK : error LNK2020: unresolved token (0A00001B) memmove
LINK : error LNK2020: unresolved token (0A00001C) memcpy
LINK : error LNK2020: unresolved token (0A00001D) delete
LINK : fatal error LNK1120: 6 unresolved externals

i must be doing something wrong, some help with this will be very wecome

thanks

searchable void* container

Amr Shahin7-Mar-06 2:58

Amr Shahin

7-Mar-06 2:58

hi every1
will u plz help me on this ...
im creating a generic container class and im implemeting it using the (void*) pointer technique

but to add a search feature, the search function should compare two (void*) variables, i dont know how to do that!

i think memcmp could be used somehow but the problem that it needs a length parameter which is now available!!

thanks already

toxcct7-Mar-06 3:06

7-Mar-06 3:06

you are on the C++/CLI forum[^], while you question is for the Visual C++ forum[^]
next time, be careful...

and for you problem, do you code in C or C++ ?
because C++ provides templates, that may certainly interrest you...

Amr Shahin7-Mar-06 3:10

Amr Shahin

7-Mar-06 3:10

oh im sorry for this mistake

anyway it doesnt really matter if its a c or c++ but for templates they are not compliant with the c++ standard so i think using the void* will be safer!!

John M. Drescher7-Mar-06 3:15

7-Mar-06 3:15

Amr Shahin wrote:
oh im sorry for this mistake

It's an easy mistake to make unless you read the main forum page that explains the topic of each forum:

http://www.codeproject.com/script/comments/forums.asp[^]

John

toxcct7-Mar-06 3:16

7-Mar-06 3:16

Amr Shahin wrote:
ut for templates they are not compliant with the c++ standard so i think using the void* will be safer!!

are you on drugs ?! WTF | :WTF:

templates are part of and are defined in the standard !!!!!
hey,, i think you should really revise you judgement about templates, and learn a bit more about them...

John M. Drescher7-Mar-06 3:22

7-Mar-06 3:22

Amr Shahin wrote:
i think using the void* will be safer!!

Templates were not finalized until the mid to late 90s so compliers created before this may have a problem with them but as long as you stick to the basics and don't use partial template specialization and a few other features you will be fine on older compilers. I have been using templates for at least 5 years starting with VC6 (which is not fully compliant but very capable of using templates). void* is definitly not the way to go if you are using c++.

John

-- modified at 12:09 Tuesday 7th March, 2006

John M. Drescher7-Mar-06 3:12

7-Mar-06 3:12

It looks like most questions for this forum are off topic...

John

-- modified at 9:16 Tuesday 7th March, 2006

toxcct7-Mar-06 3:16

7-Mar-06 3:16

John M. Drescher wrote:
It looks like most questions for this forum are off topic...

true, but if people had a look at the admin note... D'Oh! | :doh:

John M. Drescher7-Mar-06 3:24

7-Mar-06 3:24

Although I have seen it in the lounge I did not even notice it in this forum today...

John

Nemanja Trifunovic7-Mar-06 5:46

Nemanja Trifunovic

7-Mar-06 5:46

John M. Drescher wrote:
It looks like most questions for this forum are off topic...

True, but i blame MS marketing for this. Most people consider CLI to be "command line interface", not "common language..." (what the heck is I for anyway?).

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

toxcct7-Mar-06 5:51