Found in the README to http://www.lrz-muenchen.de/services/software/mathematik/gsl/fortran/
gfortran is quite picky with regards to the C binding type, i.e. it does not like use iso_c_binding complex(c_double),target :: z ! correct would be: c_double_complex however it is not failing right a way, but it is only failing when using C_LOC: type(c_ptr) :: ptr ptr = c_loc(z) Error: C kind parameter is for type REAL but symbol 'z' at (1) is of type COMPLEX ISSUES: a) The error should already printed for the declaration and not for C_LOC() (The same checking is also done for the dummy arguments of BIND(C) procedures.) b) The question is whether one needs an error or whether a warning is enough (For completeness, the author did not reply to my request to change the code of FGLS.) -- Summary: C Binding: Kind parameter checking too strict and too late Product: gcc Version: 4.4.0 Status: UNCONFIRMED Keywords: diagnostic 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=38160