When compiling the code below, gfortran emits warnings about unused variables which are not defined by the user:
module misc_utils implicit none interface toString module procedure toString_i, toString_sp end interface contains function toString_i (num) integer, intent(in) :: num character (len=30) :: toString_i write(toString_i,*) num toString_i = trim(adjustl(toString_i)) end function function toString_sp (num) real, intent(in) :: num character (len=30) :: toString_sp write(toString_sp,*) num toString_sp = trim(adjustl(toString_sp)) end function end module misc_utils ~/tmp>gfortran -Wunused -W -v -c misc_utils.f90 Reading specs from /afs/mpa/data/martin/ugcc/lib/gcc/i686-pc-linux-gnu/4.0.0/specs Configured with: /scratch/gcc/configure --quiet --prefix=/afs/mpa/data/martin/ugcc --enable-languages=c++,f95 --with-gmp=/afs/mpa/data/martin/mygmp Thread model: posix gcc version 4.0.0 20041021 (experimental) /afs/mpa/data/martin/ugcc/libexec/gcc/i686-pc-linux-gnu/4.0.0/f951 misc_utils.f90 -quiet -dumpbase misc_utils.f90 -mtune=pentiumpro -auxbase misc_utils -Wunused -W -version -o /tmp/ccSekDLb.s GNU F95 version 4.0.0 20041021 (experimental) (i686-pc-linux-gnu) compiled by GNU C version 4.0.0 20041021 (experimental). GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 misc_utils.f90:5: warning: unused parameter '.__result' misc_utils.f90:5: warning: unused parameter '.__result' Interestingly, the warnings are issued for line 5, which only contains the interface description. -- Summary: [gfortran] spurious warnings with -W -Wall Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: martin at mpa-garching dot mpg dot de CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18111