Hi Claude, On Tue, Feb 1, 2011 at 2:37 PM, Claude Quézel <cquezel@gmail.com> wrote:
I noticed that the boost::process::child does not have a default constructor. If I have a coding requirements like the following example, I would be stuck:
// Note the required default constructor boost::process::child child;
// Create a scope for the mutex guard { boost::lock_guard<boost::mutex> guard(process_launch);
// Here I must do something within guard scope // that must be done with the boost::process::launch do_something();
child = boost::process::launch(exec, args, ctx); }
The author may have his own reasons for this, but making process::child default constructable would probably break an invariant. Some libraries choose to do so and add isValid() member functions to test for true initialization. In my experience this leads to lots of testing, asserts, and generally less readable code as those objects are passed to functions, etc. In the case you mentioned, you could declare a scoped_ptr<> to the child, or if you don't want dynamic memory allocations, a boost::optional<>. This would allow child to keep its invariants and use a well-known idiom for testing validity. HTH, Nate