Effects: Constructs a pool resource object that will obtain memory from
upstream
whenever the pool resource is unable to satisfy a memory request
from its own internal data structures
. The resulting object will hold a copy of
upstream,
but will not own the resource to which
upstream points
.[
Note 1:
The intention is that calls to
upstream->allocate()
will be substantially fewer than calls to
this->allocate()
in most cases
. —
end note]
The behavior of the pooling mechanism is tuned
according to the value of the
opts argument
.