Typical issues with managed C++

[sukumarvg]

Hi all

we have unmanaged C++ third party library which needs to be used in C# Environment. hence I am writing managed C++ wrapper on top

to use it in C# environment

I came across some of the situation put me into trouble.Can any one resolve my doubts

1) I was using the pin pointers to convert from managed string (String^) to unmanaged string(char * buffer)

is it safe? are there any performance issues with this ?

If then what is the best logic to do? please see the code snippet below i used

for converting from C# string to char * buffer(unmanaged string)

bool bRet = false;
pin_ptr<const wchar_t> w_string = PtrToStringChars(s);

size_t converted_chars = 0;
size_t size_bytes = ((s->Length + 1) * 2);

if ((size_bytes / 2) <= output_len)
{
memset(output, '\0', output_len);
if (!wcstombs_s(&converted_chars, output, output_len, w_string, size_bytes))
bRet = true;
}

return bRet;

2)Can i use System::Generic::Collections such as Dictionary and List for sending data from C# to managedC++

and viceversa?

I need to send collection of datasets from managed C++ to C# code. Can i use the List to do this.
if not are there any best practices to achieve this?

3)Is it necessary to use gc when i am creating any memory in managed C++

Waiting for ur reply

Thanks in advance

Sukumar

[Alex F]

1. To convert String to char* in one line, use Marshal.StringToHGlobalAnsi Method.
2. Yes. Both languages can use any .NET types.
3. Depends on object type you need to create. Managed objects are created with gcnew and allocated on managed heap. Unmanaged objects and resources are created using native C++ ways (new, stack allocation, global variables etc.)

I hope you are working with VS2005 or later, because managed C++ language syntax was completely changed from 2003 to 2005 version. This language is now called C++/CLI. If you are working with VS2003, I strongly recommend to move to a newest VS version before writing any managed C++ code.