On 11/25/02 10:06 AM, "Peter Dimov" <[EMAIL PROTECTED]> wrote:
>> One thing missing from intrusive_ptr as implemented in 1.29 is the ability >> to avoid the add_ref at construction time. >> >> There are a number of APIs using refcounted opaque types (Apple in >> particular is fond of them) in which a function call will "pre-acquire" a >> reference for the caller. In many OS X APIs, this is designated by use of >> the term "Copy" or "Create" instead of "Get". If you think about it, > adding >> a ref before returning is necessary for flat C APIs to avoid thread >> synchronization problems. > > [...] > >> This would allow one to use this style of code: >> >> intrusive_ptr<OpaqueRefCountedString> s = >> dont_addref(CopyMenuTitle(m)); > > intrusive_ptr<OpaqueRefCountedString> s = CopyMenuTitle(m); > s->Release(); // or however it's spelled > > ? > Calling Release is semantically correct, but inefficient (in some cases prohibitively so), since we're dealing with C API calls made over a library boundary. In particular, Release() is not going to get inlined. Additionally, this idiom is so common in certain OS's that a clear one-line solution would be preferable. Perhaps "reuse_ref" would be a better choice than "dont_addref"? thanks, jim _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
