B.2  Version 5.0 to 5.1 Differences

• Full support of C11, C++11, C++14, C++17, C++20 and Fortran 2008 was completed (see Section 1.7).
• Various changes throughout the specification were made to provide initial support of Fortran 2018 (see Section 1.7).
• The OpenMP directive syntax was extended to include C++ attribute specifiers (see Section 2.1).
• The omp_all_memory reserved locator was added (see Section 2.1), and the depend clause was extended to allow its use (see Section 2.19.11).
• The target_device trait set was added to the OpenMP Context (see Section 2.3.1), and the target_device selector set was added to context selectors (see Section 2.3.2).
• For C/C++, the declare variant directive was extended to support elision of preprocessed code and to allow enclosed function definitions to be interpreted as variant functions (see Section 2.3.5).
• The declare variant directive was extended with new clauses (adjust_args and append_args) that support adjustment of the interface between the original function and its variants (see Section 2.3.5).
• The dispatch construct was added to allow users to control when variant substitution happens and to define additional information that can be passed as arguments to the function variants (see Section 2.3.6).
• To support device-specific ICV settings the environment variable syntax was extended to support device-specific variables (see Section 2.4.2 and Section 6).
• The assume directive was added to allow users to specify invariants (see Section 2.5.2).
• To support clarity in metadirectives, the nothing directive was added (see Section 2.5.3).
• To allow users to control the compilation process and runtime error actions, the error directive was added (see Section 2.5.4).
• The masked construct was added to support restricting execution to a specific thread (see Section 2.8).
• The scope directive was added to support reductions without requiring a parallel or worksharing region (see Section 2.9).
• Loop transformation constructs were added (see Section 2.11.9).
• The grainsize and num_tasks clauses for the taskloop construct were extended with a strict modifier to ensure a deterministic distribution of logical iterations to tasks (see Section 2.12.2).
• Support for the align clause on the allocate directive and allocator and align modifiers on the allocate clause was added (see Section 2.13).
• The thread_limit clause was added to the target construct to control the upper bound on the number of threads in the created contention group (see Section 2.14.5).
• The has_device_addr clause was added to the target construct to allow access to variables or array sections that already have a device address (see Section 2.14.5).
• Support was added so that iterators may be defined and used in a motion clause on a target update directive (see Section 2.14.6) or in a map clause (see Section 2.21.7.1).
• Support was added for indirect calls to the device version of a procedure or function in target regions. (see Section 2.14.7).
• The interop directive was added to enable portable interoperability with foreign execution contexts used to implement OpenMP (see Section 2.15.1). Runtime routines that facilitate use of omp_interop_t objects were also added (see Section 3.12).
• The nowait clause was added to the taskwait directive to support insertion of non-blocking join operations in a task dependence graph (see Section 2.19.5).
• Support was added for compare-and-swap and (for C and C++) minimum and maximum atomic operations through the compare clause. Support was also added for the specification of the memory order to apply to a failed comparing atomic operation with the fail clause (see Section 2.19.7).
• Specification of the seq_cst clause on a flush construct was allowed, with the same meaning as a flush construct without a list and without a clause (see Section 2.19.8).
• To support inout sets, the inoutset argument was added to the depend clause (see Section 2.19.11).
• Support for private and firstprivate as an argument to the default clause in C and C++ was added (see Section 2.21.4.1).
• The present argument was added to the defaultmap clause (see Section 2.21.7.3).
• The omp_set_num_teams and omp_set_teams_thread_limit runtime routines were added to control the number of teams and the size of those teams on the teams construct (see Section 3.4.3 and Section 3.4.5). Additionally, the omp_get_max_teams and omp_get_teams_thread_limit runtime routines were added to retrieve the values that will be used in the next teams construct (see Section 3.4.4 and Section 3.4.6).
• The omp_target_is_accessible runtime routine was added to test whether host memory is accessible from a given device (see Section 3.8.4).
• To support asynchronous device memory management, omp_target_memcpy_async and omp_target_memcpy_rect_async runtime routines were added (see Section 3.8.7 and Section 3.8.8).
• The omp_get_mapped_ptr runtime routine was added to support obtaining the device pointer that is associated with a host pointer for a given device (see Section 3.8.11).
• The omp_calloc, omp_realloc, omp_aligned_alloc and omp_aligned_calloc API routines were added (see Section 3.13).
• For the omp_alloctrait_key_t enum, the omp_atv_serialized value was added and the omp_atv_default value was changed (see Section 3.13.1).
• The omp_display_env runtime routine was added to provide information about ICVs and settings of environment variables (see Section 3.15).
• The ompt_scope_beginend value was added to the ompt_scope_endpoint_t enum to indicate the coincident beginning and end of a scope (see Section 4.4.4.11).
• The ompt_sync_region_barrier_implicit_workshare, ompt_sync_region_barrier_implicit_parallel and ompt_sync_region_barrier_teams values were added to the ompt_sync_region_t enum (see Section 4.4.4.13).
• Values for asynchronous data transfers were added to the ompt_target_data_op_t enum (see Section 4.4.4.14).
• The ompt_state_wait_barrier_implementation and ompt_state_wait_barrier_teams values were added to the ompt_state_t enum (see Section 4.4.4.27).
• The ompt_callback_target_data_op_emi_t, ompt_callback_target_emi_t, ompt_callback_target_map_emi_t and ompt_callback_target_submit_emi_t callbacks were added to support external monitoring interfaces (see Section 4.5.2.25, Section 4.5.2.26, Section 4.5.2.27 and Section 4.5.2.28).
• The ompt_callback_error_t type was added (see Section 4.5.2.30).
• The OMP_PLACES syntax was extended (see Section 6.5).
• The OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT environment variables were added to control the number and size of teams on the teams construct (see Section 6.23 and Section 6.24).