[boost] [shared_array] Initialisation - could this subtle user bug be avoided?

From: Paul Giaccone (paulg_at_[hidden])
Date: 2006-03-13 10:20:40

I had some code in my program that created and initialised a 
shared_array.  When the shared_array was deleted, the program crashed 
with an exception that suggested I had written beyond the end of the array.

I realised that the problem was I had written:

    boost::shared_array<double> foo(new double(num));

instead of:

    boost::shared_array<double> foo(new double[num]);

(For those without sharp eyes, that's parentheses instead of square 
brackets.)

The compiler was perfectly happy with this, of course, because new 
double(num) is perfectly good syntax.

Is there any way that this bug could be caught at compile time?  Perhaps 
the solution might be to provide a separate constructor (a convenience 
function) that took only a "size" parameter and did the "new" for you:

    boost::shared_array<double> foo(num);

Paul