So far very little work has been done to support Fortran 2018.
ERROR STOPstatement is permitted in a
IMPLICIT NONEstatement with an
The behavior of the
INQUIRE statement with the
specifier now conforms to Fortran 2018.
GNU Fortran supports some of the new features of the Technical Specification (TS) 29113 on Further Interoperability of Fortran with C. The wiki has some information about the current TS 29113 implementation status. In particular, the following is implemented.
See also Further Interoperability of Fortran with C.
OPTIONALattribute is allowed for dummy arguments of
RANKintrinsic is supported.
ASYNCHRONOUSattribute is compatible with TS 29113.
DIMENSION(..)). However, the array descriptor of the TS is not yet supported.
GNU Fortran supports the following new features of the Technical Specification 18508 on Additional Parallel Features in Fortran:
SUMreduction intrinsics. And the
CO_REDUCEintrinsic, except that those do not support polymorphic types or types with allocatable, pointer or polymorphic components.