🚀 go-pugleaf

"Dennis Jones" <nospam@nospam.com> wrote in message 
news:478b0076$1@newsgroups.borland.com...

> An article discussing the implementation and use of ScopeGuard was written
> by Andrei Alexandrescu and Petru Marginean and was published in CUJ in
> December 2000.

Nice article.

I had always been a little disappointed with pure RAII techniques since it 
seemed silly to have to make full class every time a new use situation 
arose.  I stuck with it though (and occassionally slipped in a well 
documented try...__finally block).

After testing ScopeGuard I might make the switch.  It even works with 
closures.

I have one itty bitty problem with using this approach.  I haven't looked 
closely enough yet to see why it's happening.  If full warnings are enabled 
(specifically -w-aus) and I use a standard RAII class (like std::auto_ptr or 
something I've made) then the following compiles in Builder without warning 
(in BCB6 and CB2007):

  class TMyAuto
  {
    private:
      char* Ptr;

    public:
      TMyAuto(char* APtr) : ptr(APtr) {}
      ~TMyAuto() { delete Ptr; }
  };

  char* c = new char;
  TMyAuto auto_c(c);

  // This also works with no warning
  // std::auto_ptr<char> auto_c(c);

However, if I use ScopeGuard I receive a W8004 warning:

  void DeleteIt(char* Ptr)
  {
    delete Ptr;
  }

  char* c = new char;
  ON_BLOCK_EXIT(&DeleteIt, c);

  // This also causes a W8004 warning
  // ScopeGuard auto_c(MakeGuard(&DeleteIt, c));

  W8004 'scopeGuard321' is assigned a value that is never used

As I said above I haven't looked too much into this.  I don't know if 
Builder should be mentioning the warning in all cases or if it follows some 
rule that ScopeGuard isn't triggering.  In any case, I still like ScopeGuard 
and will investigate the warning issue at a later date.

Clayton