C/C++ Programmer's Guide (G06.27+, H06.08+, J06.03+)

language-specifier is one of:

attribute is one of:

_alias ( "external-name " ) |

_extensible [ ( param-count ) ]

_resident | _variable

language-specifier

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

external routine being declared.

Considerations for the Native Compilers Only

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

native COBOL85, 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 the 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, these language specifiers apply:

_c, _cobol, _fortran, _pascal, _tal, and _unspecified.

• If you declare an external procedure as _unspecified, 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, in the definition, the name must not contain lowercase alphabetic characters.

Considerations for Both the Native and TNS Compilers

• Only one language specifier can be specified for a function.

• The language specifier is allowed only in function declarations, function definitions, and

function pointer declarations. However, _cobol, _fortran, _pascal, _tal, and

_unspecified are not allowed in function definitions. _c is allowed in a function definition

only if the language being compiled is C.

• For C++, a language specifier is not allowed on overloaded functions, member functions,

function templates, inline functions, or functions with default arguments.

• For a function with C-style variable argument lists, the only explicit language attribute allowed

is _c.

• The language specifier _unspecified indicates that the language is unknown and

unspecified.

attribute

specifies a function attribute.

Considerations for Both the Native and TNS Compilers

• An attribute is allowed only in function declarations, function definitions, and function

pointer declarations.

• The same attribute is not allowed to appear more than once in a function declaration.

• In C++, attributes on virtual functions are not inherited.

• A function is allowed to have multiple declarations. If the multiple declarations are incompatible,

an error message is generated. If the declarations are compatible, the attribute values are

56 C and C++ Extensions