https://msdn.microsoft.com/en-us/library/xda6xzx7.aspx
From: ozdotnet-boun...@ozdotnet.com [mailto:ozdotnet-boun...@ozdotnet.com] On Behalf Of Greg Keogh Sent: Tuesday, 24 October 2017 4:50 PM To: ozDotNet <ozdotnet@ozdotnet.com> Subject: Re: Marshalling strings This article: https://limbioliong.wordpress.com/2011/06/16/returning-strings-from-a-c-api/ Hints that the interop marshaller takes ownership of the returned string and will delete the buffer. If this is true, then it's pretty smart and invalidates our concerns about a possible leak. I'm reading more and running some experiments -- GK On 24 October 2017 at 16:28, Tony McGee <tmcgee...@gmail.com<mailto:tmcgee...@gmail.com>> wrote: My understanding would be that either the caller allocated a large enough buffer and passes it to the library in which case the callee does a copy and doesn't need to worry about it -or- the callee keeps the pointer they've given out and expects the caller to pass it back to another function to do the free/dealloc. I believe there's standard functions for allocating things like BSTR's from the COM days (SysAllocString/SysFreeString) where the callee allocates and the caller is responsible for deallocation but passing out raw wchar_t pointers without agreeing on a deallocation method isnt great. On 24 Oct 2017 15:14, "Greg Keogh" <gfke...@gmail.com<mailto:gfke...@gmail.com>> wrote: Folks, my REST web service makes calls to C++ functions in a native DLL. The functions return wchar_t* which I marshal into a managed string. The author of the C++ code doesn't know when to free the buffer he's allocated for the string (neither do I). The very last statement in his function is return char_ptr, so the function ends and the buffer becomes a leak. I consume the pointer after his function ends, so when can he delete it? Is there some trick I'm forgetting? Or are we doing it the wrong way? Greg K
