[C++][OpenMP] Proper use of "atomic directive" to lock STL container
- by conradlee
I have a large number of sets of integers, which I have, in turn, put into a vector of pointers. I need to be able to update these sets of integers in parallel without causing a race condition. More specifically. I am using OpenMP's "parallel for" construct.
For dealing with shared resources, OpenMP offers a handy "atomic directive," which allows one to avoid a race condition on a specific piece of memory without using locks. It would be convenient if I could use the "atomic directive" to prevent simultaneous updating to my integer sets, however, I'm not sure whether this is possible.
Basically, I want to know whether the following code could lead to a race condition
vector< set<int>* > membershipDirectory(numSets, new set<int>);
#pragma omp for schedule(guided,expandChunksize)
for(int i=0; i<100; i++)
{
set<int>* sp = membershipDirectory[5];
#pragma omp atomic
sp->insert(45);
}
(Apologies for any syntax errors in the code---I hope you get the point) I have seen a similar example of this for incrementing an integer, but I'm not sure whether it works when working with a pointer to a container as in my case.
