B.2  Version 5.1 to 5.2 Differences

• The explicit-task-var ICV has replaced the implicit-task-var ICV and has the opposite meaning and semantics (see Chapter 2). The omp_in_explicit_task routine was added to query if a code region is executed from an explicit task region (see Section 18.5.2).
• Major reorganization and numerous changes were made to improve the quality of the specification of OpenMP syntax and to increase consistency of restrictions and their wording. These changes frequently result in the possible perception of differences to preceding versions of the OpenMP specification. However, those differences almost always resolve ambiguities, which may nonetheless have implications for existing implementations and programs.
• For OpenMP directives, reserved the omp sentinel (see Section 3.1, Section 3.1.1 and Section 3.1.2) and, for implementation-defined directives that extend the OpenMP directives reserved the ompx sentinel for C/C++ and free source form Fortran (see Section 3.1 and Section 3.1.2) and the omx sentinel for fixed source form Fortran to accommodate character position requirements (see Section 3.1.1). Reserved clause names that begin with the ompx_ prefix for implementation-defined clauses on OpenMP directives (see Section 3.2). Reserved names in the base language that start with the omp_ and ompx_ prefix and reserved the omp and ompx namespaces (see Chapter 4) for the OpenMP runtime API and for implementation-defined extensions to that API (see Chapter 18).
• Allowed any clause that can be specified on a paired end directive to be specified on the directive (see Section 3.1), including the copyprivate clause (see Section 5.7.2) and the nowait clause in Fortran (see Section 15.6).
• For consistency with the syntax of other definitions of the clause, the syntax of the destroy clause on the depobj construct with no argument was deprecated (see Section 3.5).
• For consistency with the syntax of other clauses, the syntax of the linear clause that specifies its argument and linear-modifier as linear-modifier(list) was deprecated and the step modifier was added for specifying the linear step (see Section 5.4.6).
• The minus (-) operator for reductions was deprecated (see Section 5.5.5).
• The syntax of modifiers without comma separators in the map clause was deprecated (see Section 5.8.3).
• To support the complete range of user-defined mappers and to improve consistency of map clause usage, the declare mapper directive was extended to accept iterator-modifier and the present map-type-modifier (see Section 5.8.3 and Section 5.8.8).
• If a matching mapped list item is not found in the data environment, the pointer retains its original value as per the firstprivate semantics (see Section 5.8.6).

• The enter clause was added as a synonym for the to clause on the declare target directive, and the corresponding to clause was deprecated to reduce parsing ambiguity (see Section 5.8.4 and Section 7.8).

  ∙ Metadirectives (see Section 7.4), assumption directives (see Section 8.3), nothing directives (see Section 8.4), error directives (see Section 8.5) and loop transformation constructs (see Chapter 9) were added to the list of directives that are allowed in a pure procedure (see Chapter 3). ∙ The allocators construct was added to support the use of OpenMP allocators for variables that are allocated by a Fortran ALLOCATE statement, and the application of allocate directives to an ALLOCATE statement was deprecated (see Section 6.7). ∙ For consistency with other constructs with associated base language code, the dispatch construct was extended to allow an optional paired end directive to be specified (see Section 7.6).
• To support the full range of allocators and to improve consistency with the syntax of other clauses, the argument that specified the arguments of the uses_allocators as a comma-separated list in which each list item is a clause-argument-specification of the form allocator[(traits)] was deprecated (see Section 6.8).

• To improve code clarity and to reduce ambiguity in this specification, the otherwise clause was added as a synonym for the default clause on metadirectives and the corresponding default clause syntax was deprecated (see Section 7.4.2).

  ∙ To improve overall syntax consistency and to reduce redundancy, the delimited form of the declare target directive was deprecated (see Section 7.8.2).
• The behavior of the order clause with the concurrent parameter was changed so that it only affects whether a loop schedule is reproducible if a modifier is explicitly specified (see Section 10.3).
• Support for the allocate and firstprivate clauses on the scope directive was added (see Section 11.2).
• The ompt_callback_work callback work types for worksharing loop were added (see Section 11.5).
• To simplify usage, the map clause on a target enter data or target exit data construct now has a default map type that provides the same behavior as the to or from map types, respectively (see Section 13.6 and Section 13.7).
• The doacross clause was added as a synonym for the depend clause with the keywords source and sink as dependence-type modifiers and the corresponding depend clause syntax was deprecated to improve code clarity and to reduce parsing ambiguity. Also, the omp_cur_iteration keyword was added to represent an iteration vector that refers to the current logical iteration (see Section 15.9.6).