06.02.2013 2:57, Emil Dotchevski:
I mean that in D/Java/C#/etc you don't know when the destructor will get called automatically, which means that you're stuck with having to manually keep track of all allocated resources exactly like in C, except for memory.
scope(exit) (in C++) has similar behaviour to normal destructors, and in fact it is implemented on top of destructors. scope(failure) and scope(success) differs from scope(exit) only by additional condition - code in scope(failure) is called only when scope is exited by exception, and code in scope(success) is called only during "normal" scope exit. D's documentation says ( http://dlang.org/statement.html#ScopeGuardStatement ) : "The ScopeGuardStatement executes NonEmptyOrScopeBlockStatement at the close of the current scope, rather than at the point where the ScopeGuardStatement appears." Regarding C# and Java: they have some "workarounds" for resource management: C# has "using", and Java has "try-with-resources". Regarding C: there are also approaches to manage resources automatically, but that's another story.
While scope(exit) is some kind of ad-hoc replacement for RAII wrappers, scope(failure) and scope(success) are not. Nowadays scope(failure) and scope(success) are emulated in C++ via ScopeGuard idiom.
Could you clarify what does uncaught_exceptions_count() use look like? How is it different scope guard?
For instance, check first example at Boost.ScopeExit documentation (C++98 syntax): http://www.boost.org/doc/libs/1_53_0/libs/scope_exit/doc/html/index.html void world::add_person(person const& a_person) { bool commit = false; persons_.push_back(a_person); BOOST_SCOPE_EXIT(&commit, &persons_) { if(!commit) persons_.pop_back(); } BOOST_SCOPE_EXIT_END // ... commit = true; } Using SCOPE_FAILURE it would became (C++98 syntax): void world::add_person(person const& a_person) { persons_.push_back(a_person); SCOPE_FAILURE(&persons_) { persons_.pop_back(); } SCOPE_FAILURE_END // ... } Also, there are side-by-side examples at https://github.com/panaseleus/stack_unwinding#d-style-scope-guardsactions . -- Evgeny Panasyuk