CODEWITHSUNDEEP
c++multithreadingsortingstl
setholopolus
setholopolus

Reputation: 265

Does `std::sort()` use threading to increase its performance?

Does std::sort() typically use threading to increase its performance? I realize that this could vary from implementation to implementation. If not, why not?

Upvotes: 0

Views: 1686

Answers (1)

Igor Tandetnik
Igor Tandetnik

Reputation: 52471

[res.on.data.races]/8 Unless otherwise specified, C++ standard library functions shall perform all operations solely within the current thread if those operations have effects that are visible (4.7) to users.

/9 [ Note: This allows implementations to parallelize operations if there are no visible side effects. —end note ]

std::sort could, in principle, use parallel execution when sorting elements of fundamental type (it wouldn't be observable whether it does), but not user-defined type (unless explicitly given permission via execution policy parameter, of course). The type's operator< may not be thread-safe.

Upvotes: 1

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