copyprivate Clause

| OPENMP API Specification: "Version 5.2 -- GIT rev 95b2e3a44"

5.7.2 copyprivate Clause


Name: copyprivate	Properties: end-clause, data copying

Arguments


Name	Type	Properties

list	list of variable list item type	default

Directives

single

Semantics

The copyprivate clause provides a mechanism to use a private variable to broadcast a value from the data environment of one implicit task to the data environments of the other implicit tasks that belong to the parallel region. The eﬀect of the copyprivate clause on the speciﬁed list items occurs after the execution of the structured block associated with the associated construct, and before any of the threads in the team have left the barrier at the end of the construct. To avoid data races, concurrent reads or updates of the list item must be synchronized with the update of the list item that occurs as a result of the copyprivate clause if, for example, the nowait clause is used to remove the barrier.

In all other implicit tasks that belong to the parallel region, each speciﬁed list item becomes deﬁned with the value of the corresponding list item in the implicit task associated with the thread that executed the structured block. For variables of non-array type, the deﬁnition occurs by copy assignment. For an array of elements of non-array type, each element is copied by copy assignment from an element of the array in the data environment of the implicit task that is associated with the thread that executed the structured block to the corresponding element of the array in the data environment of the other implicit tasks.

For class types, a copy assignment operator is invoked. The order in which copy assignment operators for diﬀerent variables of class type are called is unspeciﬁed.

If a list item does not have the POINTER attribute, then in all other implicit tasks that belong to the parallel region, the list item becomes deﬁned as if by intrinsic assignment with the value of the corresponding list item in the implicit task that is associated with the thread that executed the structured block. If the list item has a type bound procedure as a deﬁned assignment, the assignment is performed by the deﬁned assignment. If the list item has the POINTER attribute then in all other implicit tasks that belong to the parallel region the list item receives, as if by pointer assignment, the same association status as the corresponding list item in the implicit task that is associated with the thread that executed the structured block.

The order in which any ﬁnal subroutines for diﬀerent variables of a ﬁnalizable type are called is unspeciﬁed.

Restrictions

Restrictions to the copyprivate clause are as follows:

All list items that appear in a copyprivate clause must be either threadprivate or private in the enclosing context.

∙ A variable of class type (or array thereof) that appears in a copyprivate clause requires an accessible unambiguous copy assignment operator for the class type.

∙ A common block that appears in a copyprivate clause must be threadprivate. ∙ Pointers with the INTENT(IN) attribute must not appear in a copyprivate clause. ∙ Any list item with the ALLOCATABLE attribute must have the allocation status of allocated when the intrinsic assignment is performed. ∙ If a list item is a polymorphic variable with the ALLOCATABLE attribute, the behavior is unspeciﬁed.

Cross References

firstprivate clause, see Section 5.4.4
private clause, see Section 5.4.3
single directive, see Section 11.1

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