2.9  scope Construct

Summary The scope construct defines a structured block that is executed by all threads in a team but where additional OpenMP operations can be specified.

Syntax

 
#pragma omp scope [clause[ [,] clause] ... ] new-line 
   structured-block
  

 
private(list) 
reduction([reduction-modifier ,] reduction-identifier : list) 
nowait
       

 
!$omp scope [clause[ [,] clause] ... ] 
   loosely-structured-block 
!$omp end scope [nowait]
  

 
!$omp scope [clause[ [,] clause] ... ] 
   strictly-structured-block 
[!$omp end scope [nowait]]
  

 
private(list) 
reduction([reduction-modifier ,] reduction-identifier : list)
       

Binding The binding thread set for a scope region is the current team. A scope region binds to the innermost enclosing parallel region. Only the threads of the team that executes the binding parallel region participate in the execution of the structured block and the implied barrier of the scope region if the barrier is not eliminated by a nowait clause.

Description All encountering threads will execute the structured block associated with the scope construct. An implicit barrier occurs at the end of a scope region if the nowait clause is not specified.

Execution Model Events The scope-begin event occurs after an implicit task encounters a scope construct but before the task starts to execute the structured block of the scope region.

The scope-end event occurs after an implicit task finishes execution of a scope region but before it resumes execution of the enclosing region.

Tool Callbacks A thread dispatches a registered ompt_callback_work callback with ompt_scope_begin as its endpoint argument and ompt_work_scope as its wstype argument for each occurrence of a scope-begin event in that thread. Similarly, a thread dispatches a registered ompt_callback_work callback with ompt_scope_end as its endpoint argument and ompt_work_scope as its wstype argument for each occurrence of a scope-end event in that thread. The callbacks occur in the context of the implicit task. The callbacks have type signature ompt_callback_work_t.

Restrictions Restrictions to the scope construct are as follows:

• Each scope region must be encountered by all threads in a team or by none at all, unless cancellation has been requested for the innermost enclosing parallel region.
• The sequence of worksharing regions, scope regions and barrier regions encountered must be the same for every thread in a team.
• At most one nowait clause can appear on a scope construct.
  ∙ A throw executed inside a scope region must cause execution to resume within the same scope region, and the same thread that threw the exception must catch it.

Cross References

• reduction clause, see Section 2.21.4.
• ompt_scope_begin and ompt_scope_end, see Section 4.4.4.11.
• ompt_work_scope, see Section 4.4.4.15.
• ompt_callback_work_t, see Section 4.5.2.5.