B.4  Version 4.0 to 4.5 Differences

• Support for several features of Fortran 2003 was added (see Section 1.7).
• A parameter was added to the ordered clause of the worksharing-loop construct (see Section 2.11.4) and clauses were added to the ordered construct (see Section 2.19.9) to support doacross loop nests and use of the simd construct on loops with loop-carried backward dependences.
• The linear clause was added to the worksharing-loop construct (see Section 2.11.4).
• The simdlen clause was added to the simd construct (see Section 2.11.5.1) to support specification of the exact number of iterations desired per SIMD chunk.
• The priority clause was added to the task construct (see Section 2.12.1) to support hints that specify the relative execution priority of explicit tasks. The omp_get_max_task_priority routine was added to return the maximum supported priority value (see Section 3.5.1) and the OMP_MAX_TASK_PRIORITY environment variable was added to control the maximum priority value allowed (see Section 6.16).
• Taskloop constructs (see Section 2.12.2 and Section 2.12.3) were added to support nestable parallel loops that create OpenMP tasks.
• To support interaction with native device implementations, the use_device_ptr clause was added to the target data construct (see Section 2.14.2) and the is_device_ptr clause was added to the target construct (see Section 2.14.5).
• To support unstructured data mapping for devices, the target enter data (see Section 2.14.3) and target exit data (see Section 2.14.4) constructs were added and the map clause (see Section 2.21.7.1) was updated.
• The nowait and depend clauses were added to the target construct (see Section 2.14.5) to improve support for asynchronous execution of target regions.
• The private, firstprivate and defaultmap clauses were added to the target construct (see Section 2.14.5).
• The declare target directive was extended to allow mapping of global variables to be deferred to specific device executions and to allow an extended-list to be specified in C/C++ (see Section 2.14.7).
• To support a more complete set of device construct shortcuts, the target parallel (see Section 2.16.16), target parallel worksharing-loop (see Section 2.16.17), target parallel worksharing-loop SIMD (see Section 2.16.18), and target simd (see Section 2.16.20), combined constructs were added.
• The if clause was extended to take a directive-name-modifier that allows it to apply to combined constructs (see Section 2.18).
• The hint clause was added to the critical construct (see Section 2.19.1).
• The source and sink dependence types were added to the depend clause (see Section 2.19.11) to support doacross loop nests.
• The implicit data-sharing attribute for scalar variables in target regions was changed to firstprivate (see Section 2.21.1.1).
• Use of some C++ reference types was allowed in some data sharing attribute clauses (see Section 2.21.4).
• The ref, val, and uval modifiers were added to the linear clause (see Section 2.21.4.6).
• Semantics for reductions on C/C++ array sections were added and restrictions on the use of arrays and pointers in reductions were removed (see Section 2.21.5.4).
• Support was added to the map clauses to handle structure elements (see Section 2.21.7.1).
• Query functions for OpenMP thread affinity were added (see Section 3.3.2 to Section 3.3.7).
• Device memory routines were added to allow explicit allocation, deallocation, memory transfers and memory associations (see Section 3.8).
• The lock API was extended with lock routines that support storing a hint with a lock to select a desired lock implementation for a lock’s intended usage by the application code (see Section 3.9.2).
• C/C++ Grammar (previously Appendix B) was moved to a separate document.