Re: Scope vs. point of construction for an object
On Oct 22, 11:59 pm, Alan McKenney <alan_mckenn...@yahoo.com> wrote:
(Cf.: "separate the declaration and construction of a local variable")
I've run into a situation with a class from a 3rd-party vendor, where:
1. There's no copy constructor or assignment operator.
2. The constructor may throw.
3. I need to use the object at various points in the code.
The sample code has the object being local and one big
"try" block around all the code that uses it. I would prefer
to have the "try" block just around where the object is
constructed, but then the object goes out of scope at
the end of the "try" block.
The obvious approach -- use a pointer and "new" -- seems sort of ugly:
T *t_ptr = 0;
try { t_ptr = new T( /* long complicated list of constructor
arguments */ ); } catch (...) { /* stuff */ }
// use t_ptr
delete t_ptr; // don't forget to delete it
Is there a way that keeps the non-pointer syntax?
Even better would be if I could put it into an object.
{ clc++m banner removed; please don't quote it. -mod }
The question as to whether to wrap this depends on what you're going
to do in the catch. If that's somewhat complicated, you may want to
wrap it. But why not just have a reference to T that is initialized
after the try/catch code. At that point, T is properly constructed.
Any subsequent code can use the reference (object) syntax instead of
the pointer syntax.
BTW, use a smart-pointer to hold the new'd object. For local scope,
auto_ptr works fine.
HTH
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