CODEWITHSUNDEEP
c++multithreadinginitialization
user2953119
user2953119

Reputation:

Variable initialization when program starts/does_not_start a thread

Could you explain the point of difference between variable initialization sequence if a program starts and does not start a thread?

sec. 3.6.2/3 N3797 c++14 working draft:

If a program starts a thread (30.3), the subsequent initialization of a variable is unsequenced with respect to the initialization of a variable defined in a different translation unit. Otherwise, the initialization of a variable is indeterminately sequenced with respect to the initialization of a variable defined in a different translation unit.

Please, give an example, explaining that rule, if it possible.

Upvotes: 0

Views: 49

Answers (1)

Mike Seymour
Mike Seymour

Reputation: 254631

Unsequenced means there is no sequence - the variables could be initialised concurrently, on different threads.

Indeterminately sequenced means that one is sequenced before the other - the variables are initialised sequentially, on the same thread - but it's not specified which is initialised first.

Upvotes: 1

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