Fortran Program units and file layout Internal subprograms
Example
A program unit which is not an internal subprogram may contain other program units, called internal subprograms.
program prog
implicit none
contains
function f()
end function f
subroutine g()
end subroutine g
end program
Such an internal subprogram has a number of features:
- there is host association between entities in the subprogram and the outer program
- implicit typing rules are inherited (
implicit noneis in effect infabove) - internal subprograms have an explicit interface available in the host
Module subprograms and external subprograms may have internal subprograms, such as
module mod
implicit none
contains
function f()
contains
subroutine s()
end subroutine s
end function f
end module mod
