B.3  Version 4.0 to 4.5 Differences

• Support for several features of Fortran 2003 was added (see Section 1.7 on page 83 for features that are still not supported).
• A parameter was added to the ordered clause of the worksharing-loop construct (see Section 2.9.2 on page 288) and clauses were added to the ordered construct (see Section 2.17.9 on page 717) 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 2.9.2 on page 288).
• The simdlen clause was added to the simd construct (see Section 2.9.3.1 on page 316) to support specification of the exact number of iterations desired per SIMD chunk.
• The priority clause was added to the task construct (see Section 2.10.1 on page 384) 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 3.2.42 on page 1141) and the OMP_MAX_TASK_PRIORITY environment variable was added to control the maximum priority value allowed (see Section 6.16 on page 1678).
• Taskloop constructs (see Section 2.10.2 on page 395 and Section 2.10.3 on page 407) 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 2.12.2 on page 451) and the is_device_ptr clause was added to the target construct (see Section 2.12.5 on page 478).
• The nowait and depend clauses were added to the target construct (see Section 2.12.5 on page 478) to improve support for asynchronous execution of target regions.
• The private, firstprivate and defaultmap clauses were added to the target construct (see Section 2.12.5 on page 478).
• 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 2.12.7 on page 513).
• To support unstructured data mapping for devices, the target enter data (see Section 2.12.3 on page 461) and target exit data (see Section 2.12.4 on page 469) constructs were added and the map clause (see Section 2.19.7.1 on page 939) was updated.
• To support a more complete set of device construct shortcuts, the target parallel (see Section 2.13.16 on page 572), target parallel worksharing-loop (see Section 2.13.17 on page 576), target parallel worksharing-loop SIMD (see Section 2.13.18 on page 581), and target simd (see Section 2.13.20 on page 589), 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 2.15 on page 619).
• The hint clause was addded to the critical construct (see Section 2.17.1 on page 626).
• The source and sink dependence types were added to the depend clause (see Section 2.17.11 on page 736) to support doacross loop nests.
• The implicit data-sharing attribute for scalar variables in target regions was changed to firstprivate (see Section 2.19.1.1 on page 777).
• Use of some C++ reference types was allowed in some data sharing attribute clauses (see Section 2.19.4 on page 842).
• 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 2.19.5.4 on page 885).
• The ref, val, and uval modifiers were added to the linear clause (see Section 2.19.4.6 on page 867).
• Support was added to the map clauses to handle structure elements (see Section 2.19.7.1 on page 939).
• Query functions for OpenMP thread affinity were added (see Section 3.2.24 on page 1092 to Section 3.2.29 on page 1106).
• 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 3.3.2 on page 1164).
• Device memory routines were added to allow explicit allocation, deallocation, memory transfers and memory associations (see Section 3.6 on page 1187).
• C/C++ Grammar (previously Appendix B) was moved to a separate document.