Using Standard Fortran Interoperability Syntax for Existing Fortran Extensions

Before the introduction of the Standard Fortran interoperability features, extensions provided by Intel® Fortran were used to facilitate programming using code written in Fortran and C. The Fortran 2003 standard defined new language features for C interoperability; in many cases, these features can be used instead of existing Intel® Fortran extensions. The following table lists the legacy Intel® Fortran extensions and shows their Standard Fortran equivalents.

Note

Existing code using legacy extensions will continue to work; however, if you are writing new code, you should use the standard syntax.

Legacy Extension	Standard Fortran Interoperability Equivalent
`ATTRIBUTES ALIAS`	Use `BIND(C,NAME="alias-name")`. The `BIND(C)` syntax also implies `ATTRIBUTES DECORATE`; the compiler applies whatever name decoration (leading or trailing underscores) that C would use for the name. If the `NAME= clause` is omitted, Fortran will use the Fortran name converted to lowercase on all platforms. If the procedure has no arguments, you must indicate that with `()`when adding `BIND`. All arguments to a routine specified as "interoperable" (with `BIND(C)`) must themselves be interoperable. You can also specify `BIND(C)` on module variables and `COMMON` blocks.
`ATTRIBUTES C`	Use `BIND(C)` (see `ALIAS` above), which has a similar effect to `ATTRIBUTES C` except that it does not change the argument passing mechanism to be by-value. Use the Fortran standard `VALUE` attribute if you need to pass by value. `BIND(C)` also specifies that small records are passed and returned as function value results the same way C would, which may be different from the Intel® Fortran default. Like `ATTRIBUTES C`, `BIND(C)` downcases the external name and adds any necessary name decoration.
`ATTRIBUTES DECORATE`	Typically used with `ATTRIBUTES ALIAS`. See `ATTRIBUTES ALIAS`above.
`ATTRIBUTES DEFAULT`	Not needed when using `BIND(C)`; the compiler always uses the semantics of the C compiler regardless of the setting of command-line options such as iface.
`ATTRIBUTES EXTERN`	Use `BIND(C)` with a module variable.
`ATTRIBUTES REFERENCE`	Not needed when using `BIND(C)`. Typically used with character arguments, or to override the implicit pass-by-value of `ATTRIBUTES C`.
`ATTRIBUTES STDCALL`	No equivalent. Use of `STDCALL` with `BIND(C)` is not supported in Intel® Fortran. If you are interfacing to `STDCALL` routines (Windows* OS on IA-32 architecture only), you must continue to use the `ATTRIBUTES` extension, along with `ALIAS` and `DECORATE` as required.
`ATTRIBUTES VALUE`	Use the Fortran-standard `VALUE` attribute . This has an additional effect when used with a Fortran procedure; the dummy argument is received by value and then copied to a temporary variable that can be modified within the procedure. Once the procedure exits, the temporary value is discarded.
`ATTRIBUTES VARYING`	No equivalent.
`%LOC` function	Use the `C_LOC` function from intrinsic module `ISO_C_BINDING`, which may be an appropriate substitute for variables. `C_FUNLOC` is the corresponding function for procedures.
`%VAL` function	Declare the argument with the `VALUE` attribute.
`%REF` function	No equivalent; this is the default when `BIND(C)` is used.