Re: Problem with heap and malloc()/free()

"Giovanni Dicanio" <>
Wed, 23 Jan 2008 10:11:53 +0100
"Zapanaz" <> ha scritto nel messaggio

The current problem, I have class StringHandler, which has a public

wchar_t * wc;

I would not expose those kind of public members; I prefer get/set methods.
They offer better encapsulation, information hiding and more robust code,

In my application class, I call a method of StringHandler which
assigns a string to this pointer,

wc = (wchar_t *)malloc(requiredBytes);
int error = MultiByteToWideChar(CP_UTF8, 0, kpcIn, -1, wc,

As Norbert wrote, you must pay attention to ::MultiByteToWideChar
parameters, and character count.
(However, to better understand this part of your code, also some sorrounding
code is needed, to better grasp the "context".)

Then in the destructor for StringHandler, I try to free this memory


And I would suggest to set wc=NULL after the freeing, so you are sure that
you don't have dangling references.

However, consider also that you may have copied your class instances, using
operator= or copy constructor.
Did you properly implement the operator= and copy constructor for your
Did you do deep-copy in these "special" methods? (like allocating a new copy
of the buffer, and copy the content from source to destination?)

A first step could be to stop using those raw C-like arrays, both malloc and
new[], and start using a robust C++ container class, like std::vector.
If you add an std::vector instance as a data member (instead of the raw
wchar_t * pointer), std::vector will take care of proper copy and cleanup.


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