C/C++ Programmer's Guide (G06.25+)

C and C++ Extensions

HP C/C++ Programmer’s Guide for NonStop Systems—429301-008

2-10

Declarations

Attribute Specifier

The attribute specifier is an HP extension. It is used for writing system-level C and C++

functions and for declaring external routines written in other languages.

The attribute specifier is applicable only in the Guardian environment.

language-specifier

A language-specifier for a function prototype specifies the language of the

body of the external routine being declared.

Considerations for Native Compilers Only

•

Native C and C++ support mixed-language programs with modules written in

the C, C++, native COBOL, and native pTAL languages. Therefore, the only

language specifiers that apply are

_c, _cobol, _tal, and _unspecified. Use

_tal to denote the pTAL language on both TNS/E and TNS/R systems.

Considerations for TNS Compilers Only

•

TNS C and C++ support mixed-language programs with modules written in C,

C++, TNS COBOL, FORTRAN, D-series Pascal, and TAL. Therefore, the

following language specifiers apply: _c, _cobol, _fortran, _pascal, _tal,

and _unspecified.

•

If you declare an external procedure as _unspecified, then the actual

procedure cannot be both written in C and compiled using the OLDCALLS

pragma.

•

If you declare an external procedure as _unspecified and that procedure is

actually written in C, then in the definition, the name must not contain

lowercase alphabetic characters.

Note. The attribute specifier is an outdated syntax for mixed-language programming and is

maintained only for compatibility. To declare external routines written in another language, you

should use the FUNCTION pragma syntax as described in FUNCTION

on page 13-36.

attribute-specifier:

[ language-specifier ] [ attribute [ attribute ]... ]

language-specifier is one of:

attribute is one of:

_alias ( "external-name " ) |

_extensible [ ( param-count ) ]

_resident | _variable