requires Directive

| OPENMP API Specification: "Version 5.2 -- GIT rev 95b2e3a44"

8.2 requires Directive


Name: requires	Association: none
Category: informational	Properties: default

Clause groups

requirement

Semantics

The requires directive speciﬁes features that an implementation must support for correct execution and requirements for the execution of all code in the current compilation unit. The behavior that a requirement clause speciﬁes may override the normal behavior speciﬁed elsewhere in this document. Whether an implementation supports the feature that a given requirement clause speciﬁes is implementation deﬁned.

The clauses of a requires directive are added to the requires trait in the OpenMP context for all program points that follow the directive.

Restrictions

The restrictions to the requires directive are as follows:

All requires directives in the same compilation unit that specify the atomic_default_mem_order requirement must specify the same argument.
Any requires directive that speciﬁes a reverse_offload, unified_address, or unified_shared_memory requirement must appear lexically before any device constructs or device routines.
A requires directive may not appear lexically after a context selector in which any clause of the requires directive is used.
Either all compilation units of a program that contain declare target directives, device constructs or device routines or none of them must specify a requires directive that speciﬁes the reverse_offload, unified_address or unified_shared_memory requirement.
A requires directive that speciﬁes the atomic_default_mem_order requirement must not appear lexically after any atomic construct on which memory-order-clause is not speciﬁed.

∙ The requires directive may only appear at ﬁle scope.

∙ The requires directive may only appear at ﬁle or namespace scope.

∙ The requires directive must appear in the speciﬁcation part of a program unit, after any USE statement, any IMPORT statement, and any IMPLICIT statement, unless the directive appears by referencing a module and each clause already appeared with the same arguments in the speciﬁcation part of the program unit.

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