How do you prevent memory leaks?

[John Cruz]

Can anyone give me hints on how to prevent memory leaks when programming
in VC++. also, how would you know if your program is causing memory leaks?
well, anyways thanks for the input.

[Danny Kalev]

John Cruz wrote:
>
> Can anyone give me hints on how to prevent memory leaks when programming
> in VC++.
Simply by not creating leaks in the first place. Seriously, memory leaks
aren't a Bad Karma; they are always a result of negligent programming.
Minimize the use of direct memory allocations; use standard container
classes such as string and vector and think thrice before you allocate
anything on the free-store -- in most cases you will find that you can
just as well allocate it on the stack or statically.

also, how would you know if your program is causing memory leaks?
> well, anyways thanks for the input.

There's way to know that for sure, really. In most cases, a leaking
program that runs for a long time simply leaks so much memory that the
entire OS crashes. There are commercial tools that seemingly detect
memory leaks but they are not very reliable so my advice is to simply
stick to good programming practices and minimize the chances of leaks in
the first place. Give me any memory leak and I'll show you how it could
have been prevented by using a standard feature of C++. It's as simple
as that.

Danny

[ralph]

"John Cruz" <Baller187_69@hotmail.com> wrote:
>
>
> Can anyone give me hints on how to prevent memory leaks when programming
>in VC++. also, how would you know if your program is causing memory leaks?
>well, anyways thanks for the input.

Read up on using DEBUG NEW. Install the CRT source code.

[Dmitrij]

> Can anyone give me hints on how to prevent memory leaks when programming
>in VC++.
Try use std::auto_ptr template for pointers.
>also, how would you know if your program is causing memory leaks?
>well, anyways thanks for the input.
There are many program that do this work. For example BoundsChecker.

[Djalma Santos Filho]

Danny Kalev <dannykk@inter.net.il> wrote:

Give me any memory leak and I'll show you how it could
>have been prevented by using a standard feature of C++. It's as simple
>as that.
>
>Danny

Hi Danny

I found very interesting what you wrote, but I really cannot figure out a
way to avoid the memory leak produced by my example code bellow, if the caller
of my method does not deallocate the char*. Please help me, I really need
to return a char* the way I did.

Thanks

char* CClickBankingErro::MensagemErro()
{
char MsgBuffer[1000];
ostrstream MsgStream(MsgBuffer,1000);
MsgStream.seekp(0);
MsgStream << "Erro " << CodigoErro << endl;

if (strlen(m_ContextoClickBanking) > 0)
MsgStream << m_ContextoClickBanking << endl;

if (strlen(m_Descricao) > 0)
MsgStream << m_Descricao << endl;

if (strlen(Descricao) > 0)
MsgStream << m_InformacaoAdicional << endl;

MsgStream << ends;

return (_strdup(MsgBuffer));
}

[Danny Kalev]

It's simple. How about:

void CClickBankingErro::MensagemErro(string & str)
{
string MsgBuffer;
ostrstream MsgStream(MsgBuffer,1000);
MsgStream.seekp(0);
MsgStream << "Erro " << CodigoErro << endl;

if (strlen(m_ContextoClickBanking) > 0)
MsgStream << m_ContextoClickBanking << endl;

if (strlen(m_Descricao) > 0)
MsgStream << m_Descricao << endl;

if (strlen(Descricao) > 0)
MsgStream << m_InformacaoAdicional << endl;

MsgStream << ends;

str=MsgBuffer;
}


(in fact, using a string you can simplify and improve the code of this
function further, e.g., by eliminating all strlen() calls but I'm
showing only how to avoid memory leaks).

Danny