[execpol.parunseq]

# 26 Algorithms library [[algorithms]](./#algorithms)

## 26.3 Parallel algorithms [[algorithms.parallel]](algorithms.parallel#execpol.parunseq)

### 26.3.6 Execution policies [[execpol]](execpol#parunseq)

#### 26.3.6.5 Parallel and unsequenced execution policy [execpol.parunseq]

[🔗](#lib:execution::parallel_unsequenced_policy)

`class execution::parallel_unsequenced_policy { unspecified };
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L744)

The class execution​::​parallel_unsequenced_policy is an execution policy type
used as a unique type to disambiguate parallel algorithm overloading and
indicate that a parallel algorithm's execution may be parallelized and
vectorized[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/algorithms.tex#L750)

During the execution of a parallel algorithm with
the execution​::​parallel_unsequenced_policy policy,
if the invocation of an element access function exits via an exception,terminate is invoked ([[except.terminate]](except.terminate "14.6.2 The std​::​terminate function"))[.](#2.sentence-1)