On 10/24/2010 5:16 AM, Simen kjaeraas wrote:
Austin Hastings <[email protected]> wrote:
If Decider uses Option1.sizeof, does any Option1 code get emitted?
For sizeof to be known, the template would have to be instantiated, yes.
Instantiated does not necessarily imply emitting code, I think. (Of
course, this is why I asked - to find out the compiler behavior and
expectations.)
If Decider uses a static method of Option1, does any more of the
Option1 code get emitted?
As with the first two, it would have to be instantiated.
Now, I have the feeling this is not really what you're asking for. What
do you mean by 'code gets emitted'? Perhaps you could give a reduced
example?
What I am trying to do is to pass a set of expected behavior to a
template. The template would make a decision based on memory versus
performance as to which of several possible implementations to use.
For example, a list might be implemented as a dynamic array, or as a
linked list (or ... or... or...).
If I asked for a list with single-ended insert/remove, then a dynamic
array is going to win on overhead. If I ask for insert-in-the-middle,
then the linked list would win on performance.
Ideally, each of the option templates would somehow provide a set of
metrics so I can ask "hey, for 100 elements, what are your
memory/performance metrics?"
Which leads to wondering how much of the metric has to be outside the
option template to avoid inadvertently generating extra object code that
won't get used.
=Austin
