why memory leak here?

[Vivienne]

Below is a function that convert a System::String to basic string. VC
+
+ reports memory leaking in this function. But I don't know why?

void SStringToBstring(System::String ^ s, std::string& os ){

using namespace Runtime::InteropServices;
pin_ptr<const wchar_twch = PtrToStringChars(s);
size_t convertedChars = 0;
size_t sizeInBytes = ((s->Length + 1) * 2);
errno_t err = 0;
char *ch = (char *)malloc(sizeInBytes);
err = wcstombs_s(&convertedChars, ch, sizeInBytes, wch,
sizeInBytes);

os = native_os; //here is the position where memory leaks!
free(ch);
}

can someone tell me why? and how to edit it?

Vivienne

[Ian Collins]

Vivienne wrote:

Below is a function that convert a System::String to basic string. VC
+
+ reports memory leaking in this function. But I don't know why?

void SStringToBstring(System::String ^ s, std::string& os ){

What's that? It isn't C++.

>
os = native_os; //here is the position where memory leaks!

You don't appear to have included the declaration of native_os.

--
Ian Collins.

[Vivienne]

sorry, I made a mistake.
it should be
os = ch;
free(ch);

however it also report memory leak.

[Ian Collins]

Vivienne wrote:

sorry, I made a mistake.
it should be
os = ch;
free(ch);

however it also report memory leak.

Please retain enough context for your reply to make sense.

You haven't explained the bizarre syntax in the function parameters.

Why do you use malloc rather than new?

Please copy and paste the exact code that gives the problem.

--
Ian Collins.

[Old Wolf]

On Sep 18, 3:47 pm, Vivienne <[e-mail]:

+ reports memory leaking in this function. But I don't know why?

Well your code uses lots of non-standard features so
it is hard to say anything with certainty. However...

void SStringToBstring(System::String ^ s, std::string& os ){

using namespace Runtime::InteropServices;
pin_ptr<const wchar_twch = PtrToStringChars(s);
size_t convertedChars = 0;
size_t sizeInBytes = ((s->Length + 1) * 2);
errno_t err = 0;
char *ch = (char *)malloc(sizeInBytes);
err = wcstombs_s(&convertedChars, ch, sizeInBytes, wch,
sizeInBytes);

os = native_os; //here is the position where memory leaks!

(I guess you mean, os = ch)

In the standard version of wcstombs(), the output
is not null-terminated if the output buffer is entirely
filled with valid characters. Perhaps this happens in
your example, you might want to ensure 'ch'
is terminated before assigning it to 'os', or
you could pass a length to the std::string constructor.

If you're still stuck then post a complete program
that compiles and doesn't include any system-specific
stuff. If you cannot do this, then asking on a Microsoft
newsgroup would be the way to go.

[Ron Natalie]

Ian Collins wrote:

You haven't explained the bizarre syntax in the function parameters.

It's a microsnotism for "managed" C++.
You need to take this to a .NET related group.