db, err := sql.Open("postgres", "…") if err != nil { log.Fatalln(err) } defer db.Close() tpl, err := template.ParseGlob("") if err != nil { log.Fatalln(err) } If template.ParseGlob("") returns...

I'm attempting to write a simple ScopeGuard based on Alexandrescu concepts but with c++11 idioms. namespace RAII { template< typename Lambda > class ScopeGuard { mutable bool committed;...

I'm using GCC 7.3.1, but also tested on coliru, which I believe is version 9.2.0. Build with the following: g++ -fsanitize=address -fno-omit-frame-pointer rai.cpp Here's rai.cpp: #include <i...

C++ classes provide RAII idiom. Therefore you don't have to care about exceptions: void function() { // The memory will be freed automatically on function exit std::vector<int> vector(1000...

In cppref, the following holds until C++17: code such as f(std::shared_ptr<int>(new int(42)), g()) can cause a memory leak if g gets called after new int(42) and throws an exception, whi...

While writing some code targeting C++17, I kind of hit a stumbling block determining the exception-safety of an operation merging two compatible std::unordered_maps. Per the current working draft, ...

Just to clarify, using make_unique only adds exception safety when you have multiple allocations in an expression, not just one, correct? For example void f(T*); f(new T); is perfectly exceptio...

In Herb Sutter's book Exceptional C++ (1999), he has words in item 10's solution: "Exception-unsafe" and "poor design" go hand in hand. If a piece of code isn't exception-safe, that's generally ...

Exceptions in C++ don't need to be caught (no compile time errors) by the calling function. So it's up to the developer's judgment whether to catch them using try/catch (unlike in Java). Is there a...

Within the scope of a member function, I want to temporarly set a member variable to a certain value. Then, when this function returns, I want to reset this member variable to a given known value....

Every looked at scope guard so far has a guard boolean variable. For example, see this discussion: The simplest and neatest c++11 ScopeGuard But a simple guard works (gcc 4.9, clang 3.6.0): templ...

I have a function that operates on a big chunk of data passed in as a sink argument. My BigData type is already C++11-aware and comes with fully functional move constructor and move assignment impl...

I have some code which need to be thread safe and exception safe. The code below is a very simplified version of my problem : #include <mutex> #include <thread> std::mutex mutex; int ...

std::tie returns a tuple of references, so you can do the following: int foo, bar, baz; std::tie(foo, bar, baz) = std::make_tuple(1, 2, 3); This is similar to foo, bar, baz = (1, 2, 3) in Python...

My understanding is that C++ implicitly generated assignment operator does a member-wise copy (this seems confirmed also by this answer). But, if during a member copy an exception is thrown (e.g. b...

Consider the following: std::vector<std::unique_ptr<int>> ptrsToInts; ptrsToInts.emplace_back(new int); If reallocation occurs in the vector, and that fails (throwing std::bad_alloc)...

Yes, I've looked at the C++ standards that I could find (or the drafts), but I'm not finding any comprehensive of the exception guarantees given by STL containers. All I can find are occasional sec...

I keep reading that swap() operation, like this for example: template<class T> void swap (T &a, T &b) { T temp (a); a = b; b = temp; } is problematic when we are dealing with E...

In an old blog entry titled Cleaner, more elegant, and harder to recognize, the author states: In C++ it's not quite so bad because C++ exceptions are raised only at specific points during execu...

The strong exception safety guarantee says that an operation won't change any program state if an exception occurs. An elegant way of implementing exception-safe copy-assignment is the copy-and-swa...