Re: [boost] [shifted_ptr] "new shifted<T>"

From: Phil Bouchard (philippe_at_[hidden])
Date: 2008-06-10 01:23:50

"Phil Bouchard" <philippe_at_[hidden]> wrote in message 
news:g2irdo$uv5$1_at_ger.gmane.org...

> Now I added a PowerPoint presentation comparing the pointer with all other 
> existing memory managers out there:
> sandbox/shifted_ptr/libs/example/doc/ShiftedPointer.ppt

Ok I just updated the doc again with a more complete version.

> While writing it I came to realize the mark & sweep algorithm is deleting 
> objects even if they are still parent of an object still being referenced 
> from the stack.  Suppose for example I got a widget having a std::string 
> as a member.  This means if the stack refers to the buffer of the string 
> but nobody points to the widget anymore then the string buffer will be 
> deleted and thus a segfault will occur.

[...]

Sorry, this is a bad example.  But imagine we have widgets piled up on each 
other and the last one is a popup dialog box.  If the only referenced one is 
the popup one then all parent widget are going to be deleted if it is 
handled by the mark & sweep algorithm.

Another example would be a this pointer being part of that parent object; no 
pointers from the stack are referencing it only the this pointer being 
cached in a register.  Registers aren't handled by garbage collectors.

-Phil