As reported by Mike Kumbera in http://gcc.gnu.org/ml/fortran/2007-04/msg00116.html
gfortran 4.2 and 4.3 chokes on: external pfname character ((136)) pfname with the the error message: Automatic character length function 'pfname' at (1) must have an explicit interface Using "character(136) pfname" works. This works with gfortran 4.1.2 and g77 and with all other compilers tested. Example by Mike Kumbera: ---------------------------- subroutine pfb() implicit none external pfname ! Fails on gfortran 4.3 & 4.2 with ! Error: Automatic character length function 'pfname' at (1) must have an explicit interface character ((136)) pfname ! character ((129+7)) pfname ! Works for both 4.2 and 4.3 ! character (136) pfname return end -- Summary: [Regression 4.2, 4.3] character((constant expression)) for external function Product: gcc Version: 4.3.0 Status: UNCONFIRMED Keywords: rejects-valid 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=31540