19 General utilities library [utilities]

19.18 Execution policies [execpol]

19.18.4 Sequenced execution policy [execpol.seq]

class execution::sequenced_­policy { unspecified };
The class execution::sequenced_­policy is an execution policy type used as a unique type to disambiguate parallel algorithm overloading and require that a parallel algorithm's execution may not be parallelized.
During the execution of a parallel algorithm with the execution::sequenced_­policy policy, if the invocation of an element access function exits via an uncaught exception, terminate() shall be called.