"MrAsm" <mrasm@usa.com> wrote in message
news:5akk7311l2bch65l9s6ig363t9dmsgsp9e@4ax.com...
On Thu, 21 Jun 2007 10:29:38 +0100, "Anthony Jones"
<Ant@yadayadayada.com> wrote:
Class CMyClass
{
private:
char * m_str;
public:
CMyClass(char * str)
{
m_str = str;
}
~CMyClass(void)
{
// Do I need to anything with m_str
}
}
In addition to what SvenC wrote, I'd like to add that, if you use raw
pointers (like tha 'char *'), you also need to implement a copy
constructor and operator= in your class, e.g.:
// Copy ctor
CMyClass( const CMyClass & );
// operator=
CMyClass & operator=( const CMyClass & );
and maybe also define your destructor to be 'virtual', to be safe e.g.
with inheritance:
virtual ~CMyClass();
C++ has several subtle things, that you don't find in C# or
Javascript... You'd better taking a good C++ book and study it and
*write* lots of code (and debug it, to learn a lot also from your
errors).
I wish you a great experience learning C++!
MrAsm
Thanks guys for your input. I had my suspicion that the answer is
ultimately 'go read a book' however that (along with using the Web) is
what
I am doing. As you've guessed I spend most of my time writing Javascript
and I will continue to do so. However I'm also required to maintain and
developer an ISAPI filter which up to now has be fairly basic but is
getting
more complex.
I dumbed down the example in a (failed) attempt to focus on a particular
area which so far in my studies seems somewhat ambigous. I'm hoping that
some one can say something in such that the penny will drop. Let me bring
up the detail a little (and ditch the distracting string stuff in real
code
I'm using CString).
My main focus is the behaviour of the return of a function. Nothing I've
read so far explains step by step what actually happens when returning a
object. Here is better example:-
Crypto.h
=======
class Crypto
{
public:
Crypto();
~Crypto();
//Public methods here
private:
HCRYPTPROV m_hProv;
};
Crypto.cpp
=========
#include "StdAfx.h"
#include "Crypto.h"
Crypto::Crypto(void)
{
m_hProv = 0;
CryptAcquireContext(&m_hProv, 0, 0, PROV_RSA_FULL,
CRYPT_MACHINE_KEYSET | CRYPT_SILENT |
CRYPT_VERIFYCONTEXT);
};
Crypto::~Crypto(void)
{
if (m_hProv != 0) CryptReleaseContext(m_hProv, 0);
};
// Other method implementations here
Now I use this class like this:-
void a()
{
Crypto oCryptoInA;
oCryptoInA = b();
}
Crypto b()
{
Crypto oCryptoInB;
return oCryptoInB;
}
Now at guess the sequence of events on return in b is:-
Destructor of Crypto is called where this is oCryptoInA.
Nope. oCryptoInA is still alive until it leaves scope.
Destructor of Crypto is called where this is oCryptoInB.
No, actually this is called earlier. oCryptoInB is copied into a temporary
DuplicateHandle to get a copy of the right-hand-side's handle. But be