Crash: "pointer being freed was not allocated" on UIElement double click about urho HOT 9 CLOSED

Looks like this line of code causes the crash: https://github.com/xamarin/urho/blob/master/Samples/Samples/InProgress/02_HelloGUI.cs#L174 if (comment only L174 - the crash won't reproduce)

Thus the problem is in the:

[DllImport ("mono-urho")]
internal static extern string UIElement_GetName (IntPtr handle);

from urho.

Probably, all bridge.cpp methods returning const char * have same behavior.

from urho.

Can be fixed by duplicating string:

DllExport const char *
UIElement_GetName (Urho3D::UIElement *_target)
{
    return _target->GetName ().CString ();
}

to

DllExport const char *
UIElement_GetName (Urho3D::UIElement *_target)
{
    return strdup (_target->GetName ().CString ());
}

from urho.

better solution without strdup:

[DllImport ("mono-urho", CallingConvention = CallingConvention.Cdecl)]
internal static extern string UIElement_GetName (IntPtr handle);

private string GetName ()
{
       return UIElement_GetName (handle);
}

to

[DllImport ("mono-urho", CallingConvention = CallingConvention.Cdecl)]
internal static extern IntPtr UIElement_GetName (IntPtr handle);

private string GetName ()
{
       return Marshal.PtrToStringAnsi(UIElement_GetName (handle));
}

from urho.

umm... this also works (setting CharSet):

[DllImport ("mono-urho", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
internal static extern string UIElement_GetName (IntPtr handle);

from urho.

Fixed with strdup.

from urho.

Late to the party, but wouldn't a custom marshaller work better than strduping?

https://github.com/libgit2/libgit2sharp/blob/vNext/LibGit2Sharp/Core/Utf8Marshaler.cs#L18

from urho.

@migueldeicaza ^

The reasoning is not leaking anything in case something in Urho itself calls methods which would do the strdup, but never clean it up.

from urho.

I think that would work, I will keep it in mind. I need to measure if the generated code would be larger than what we have (in particular on iOS)

from urho.