It would be nice to check this at compile-time, if possible (although a lot of compilers don't do this).
$ cat format.f90 program main integer :: i i = 42 print '(F10.4)', i end program main $ gfortran format.f90 $ ./a.out At line 4 of file format.f90 Fortran runtime error: Expected REAL for item 2 in formatted transfer, got INTEGER (F10.4) ^ $ gfortran -v Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../../gcc/trunk/configure --prefix=/home/ig25 --enable-languages=c,fortran Thread model: posix gcc version 4.2.0 20060716 (experimental) -- Summary: Check format mismatches at compile time Product: gcc Version: 4.2.0 Status: UNCONFIRMED Keywords: diagnostic Severity: enhancement Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tkoenig at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28397