https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41227
--- Comment #14 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> --- (In reply to rguent...@suse.de from comment #13) > Does it need to inter-operate with > extern struct { struct { int i; } a; } a; No, I don't read anything in the standard that would allow this. > extern union { int i; } a; No, per F2008 15.3.4 ΒΆ3: "There is no Fortran type that is interoperable with a C union type."