Declaration of Extrinsic Program Units

H601 function-stmt	is [ prefix ] FUNCTION function-name ( [ dummy-arg-name-list ] ) [ RESULT ( result-name ) ]
H602 subroutine-stmt	is [ prefix ] SUBROUTINE subroutine-name [ ( [ dummy-arg-list ] ) ]
H603 prefix	is prefix-spec [ prefix-spec ] ...
H604 prefix-spec	is type-spec or RECURSIVE or PURE or ELEMENTAL or extrinsic-prefix

• Within any HPF external-subprogram, every internal-subprogram must be of the same extrinsic kind as its host and any internal-subprogram whose extrinsic kind is not given explicitly is assumed to be of that extrinsic kind.

H605 program-stmt	is [ extrinsic-prefix ] PROGRAM program-name
H606 module-stmt	is [ extrinsic-prefix ] MODULE module-name
H607 block-data-stmt	is [ extrinsic-prefix ] BLOCK DATA [ block-data-name ]

• Every module-subprogram of any HPF module must be of the same extrinsic kind as its host, and any module-subprogram whose extrinsic kind is not given explicitly is assumed to be of that extrinsic kind.
• Every internal-subprogram of any HPF main-program or module-subprogram must be of the same extrinsic kind as its host, and any internal-subprogram whose extrinsic kind is not given explicitly is assumed to be of that extrinsic kind.

H608 extrinsic-prefix	is EXTRINSIC ( extrinsic-spec )
H609 extrinsic-spec	is extrinsic-spec-arg-list or extrinsic-kind-keyword
H610 extrinsic-spec-arg	is language or model or external-name
H611 language	is [ LANGUAGE = ] scalar-char-initialization-expr
H612 model	is [ MODEL = ] scalar-char-initialization-expr
H613 external-name	is [ EXTERNAL_NAME = ] scalar-char-initialization-expr

• In an extrinsic-spec-arg-list, at least one of language, model, or external-name must be specified and none may be specified more than once.
• If language is specified without LANGUAGE=, language must be the first item in the extrinsic-spec-arg-list. If model is specified without MODEL=, language without LANGUAGE= must be the first item and model must be the second item in the extrinsic-spec-arg-list. If external-name is specified without EXTERNAL_NAME=, language without LANGUAGE= must be the first item and model without MODEL= must be the second item in the extrinsic-spec-arg-list.
• The forms with LANGUAGE=, MODEL=, and EXTERNAL_NAME= may appear in any order except as prohibited above.

  Note that these rules for extrinsic-spec-arg-list are as if EXTRINSIC were a procedure with an explicit interface with a dummy-arg-list of LANGUAGE, MODEL, EXTERNAL_NAME, each of which were OPTIONAL.

• In language, values of scalar-char-initialization-expr may be:
  • "0DHPF"0D, referring to the HPF language; if a model is not explicitly specified, the model is implied to be "0DGLOBAL"0D;
  • "0DFORTRAN"0D, referring to the ANSI/ISO standard Fortran language; if a model is not explicitly specified, the model is implied to be "0DSERIAL"0D;
  • "0DF77"0D, referring to the former ANSI/ISO standard FORTRAN 77 language; if a model is not explicitly specified, the model is implied to be "0DSERIAL"0D;
  • "0DC"0D, referring to the ANSI standard C programming language; if a model is not explicitly specified, the model is implied to be "0DSERIAL"0D; or
  • an implementation-dependent value with an implementation-dependent implied model.

  Note that, for most implementations, "0DC"0D will only be allowed for function-stmts and subroutine-stmts occurring in an interface-body.

• If language is not specified it is the same as that of the host scoping unit.
• In model, values of scalar-char-initialization-expr may be:
  • "0DGLOBAL"0D, referring to the global model,
  • "0DLOCAL"0D, referring to the local model,
  • "0DSERIAL"0D, referring to the serial model, or
  • an implementation-dependent value.

• If model is not specified or implied by the specification of a language, it is the same as that of the host scoping unit.
• All languages and models whose names begin with the three letters HPF are reserved for present or future definition by this specification and its successors.
• In external-name, the value of scalar-char-initialization-expr is a character string whose use is determined by the extrinsic kind. For example, an extrinsic kind may use the external-name to specify the name by which the procedure would be known if it were referenced by a C procedure. In such an implementation, a user would expect the compiler to perform any transformations of that name that the C compiler would perform. If external-name is not specified, its value is implementation-dependent.

H614 extrinsic-kind-keyword

is HPF or HPF_LOCAL or HPF_SERIAL

• EXTRINSIC(HPF) is equivalent to EXTRINSIC("0DHPF"0D,"0DGLOBAL"0D). In the absence of an extrinsic-prefix an HPF compiler interprets a compilation unit as if it were of extrinsic kind HPF. Thus, for an HPF compiler, specifying EXTRINSIC(HPF) or EXTRINSIC("0DHPF"0D,"0DGLOBAL"0D) is redundant. Such explicit specification may, however, be required for use with a compiler that supports multiple extrinsic kinds.
• EXTRINSIC(HPF_LOCAL) is equivalent to EXTRINSIC("0DHPF"0D,"0DLOCAL"0D). A
  main-program whose extrinsic kind is HPF_LOCAL behaves as if it were a subroutine of extrinsic kind HPF_LOCAL that is called with no arguments from a main program of extrinsic kind HPF whose executable part consists solely of that call.
• EXTRINSIC(HPF_SERIAL) is equivalent to EXTRINSIC("0DHPF"0D,"0DSERIAL"0D). A main-program whose extrinsic kind is HPF_SERIAL behaves as if it were a subroutine of extrinsic kind HPF_SERIAL that is called with no arguments from a main program of extrinsic kind HPF whose executable part consists solely of that call.
• All extrinsic-kind-keywords whose names begin with the three letters HPF are reserved for present or future definition by this specification and its successors.