Allocatable character variables in Fortran

Question

My code (stripped down to what I think is relevant for this question) is

PROGRAM test

IMPLICIT NONE

CHARACTER(len=37) input
CHARACTER(len=:), allocatable :         


        

Answer 1

This

character (len=:), allocatable :: input_trim

is certainly syntactically correct in Fortran 2003. You don't say what the error that gfortran raises is, so I can't comment on why it doesn't accept the line -- perhaps you have an old version of the compiler installed.

With an up-to-date Fortran compiler (eg Intel Fortran v14.xxx) you don't need to allocate the character variable's size prior to assigning to it, you can simply write

input_trim = trim(input)

Note that

read(*,*) input_trim

won't work.

Answer 2

With Absoft Fortran, this compiles (haven't run with it yet):

character,dimension(:),allocatable::Line_for_IO !Metcalf,Reid,Cohen p. 107, w/mods
if(allocated(Line_for_IO)) deallocate(Line_for_IO)
allocate(Line_for_IO(7*n+40))