c++ - Correctly using an accessor in tbb -

i have list of items insert tbb's concurrent hash map. what's correct way of using accessor, way 1 or 2?

// way 1 (a list of (keys,values)) {     map::accessor a;      myhashtable.insert(a, key);     (a->second).push_back(value);      a.realease(); }  // way 2  map::accessor a;  (a list of (keys,values)) {      myhashtable.insert(a, key);     (a->second).push_back(value);      a.realease(); } 

basically either, since explicitly call accessor::release(). generally, code quality point of view, i'd limit scope of locking minimal necessary region since code extended further in unexpected way or/and exception-safety issue.

the third way without explicit release is:

// way 3 (a list of (keys,values)) {     map::accessor a;      myhashtable.insert(a, key);     (a->second).push_back(value); } 

p.s. try avoid using of accessor in serial code when possible, e.g. use insert(value_type) form. reduce overheads of thread-safety