Thread function must return void
The function used to initialize threads cannot retrun anything but void.
void partial_sum(int st, int ed, boost::uint64_t& total) {
for (int i = st; i < ed; ++i)
total += i;
}
In the funciton above, partial_sum is adding the sum of [st, ed) on total.
Boost Reference need to be used with “&” in function head
However, only using boost::uint64_t& will not make your program work in the way expected. When initializing the thread, we need to add boost::ref() as well:
boost::thread t1(partial_sum, 0, 500000000, boost::ref(sum_1));
Alternative way: pointer
Thread function definition:
void partial_sum(int st, int ed, boost::shared_ptr<boost::uint64_t> total) {
for (int i = st; i < ed; ++i)
*total += i;
}
To initialize the thread:
auto sum_1 = boost::make_shared<boost::uint64_t>(0);
boost::thread t1(partial_sum, 0, 500000000, sum_1);
After this function, *sum_1 will become the sum value.
