Is std::vector::clear()-ing an inner vector of a 2-D vector thread safe?

Question

Let's say I have an object threadWork initialised as:

vector< vector<myType> > threadWork(N_THREADS, vector<myType>());

I then deploy N_THREADS threads, each performing writes via vector::push_back()s to a separate element (its own vector<myType> object) of threadWork.

One thread then calls vector::clear() on its element of threadWork. Does this invalidate the writes of the other threads to their element? i.e Can vector::clear() called on one element of threadWork alter the memory allocation of the other elements of threadWork, such that a thread may be writing to invalid addresses as a result?

If there is no concurrent access to the **same** element, there is no data race. — StoryTeller - Unslander Monica, Aug 06 '17 at 21:19

score 1 · Accepted Answer · answered Aug 06 '17 at 21:19

1

This is completely fine. Altering an element of the outer vector does not affect the other elements in any way.

answered Aug 06 '17 at 21:19

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Is std::vector::clear()-ing an inner vector of a 2-D vector thread safe?

1 Answers1