Throwing exceptions from constructors
Solution 1:
Yes, throwing an exception from the failed constructor is the standard way of doing this. Read this FAQ about Handling a constructor that fails for more information. Having a init() method will also work, but everybody who creates the object of mutex has to remember that init() has to be called. I feel it goes against the RAII principle.
Solution 2:
If you do throw an exception from a constructor, keep in mind that you need to use the function try/catch syntax if you need to catch that exception in a constructor initializer list.
e.g.
func::func() : foo()
{
try {...}
catch (...) // will NOT catch exceptions thrown from foo constructor
{ ... }
}
vs.
func::func()
try : foo() {...}
catch (...) // will catch exceptions thrown from foo constructor
{ ... }