I think __GFORTRAN__ is undocumented - at least I could not find any .texi where it is documented.
I think it should be documented in doc/cpp.texi, possibly also in fortran/*texi. -- Summary: Document __GFORTRAN__ Product: gcc Version: 4.3.0 Status: UNCONFIRMED Keywords: documentation Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: burnus at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33303