[Mono-dev] Embedding Mono + SWIG string return values leads to bad free

[Robert Jordan]

Hi,

Ewen Cheslack-Postava wrote:
> This seems to work well on Linux and Mac OS X, but on Windows it
> causes an exception when the GC tries to free that same memory.  I've
> verified that I do in fact get a new copy of the string out at a
> different address from the original.  It looks like maybe the string
> is just being double freed.  The specific error I get (only in the
> Visual Studio debugger) is:
> 
> HEAP[x.exe]: Invalid Address specified to RtlFreeHeap( 01E00000, 00166C78 )

On Windows, the char* returned by the C# method must be freed with
GlobalFree (). You're probable using free () which is expecting
that the memory was allocated from another heap.

This is for compatibility with MS.NET.

Robert