fix(file_t): write_lines checks if already open

Author: rouson

src/julienne/julienne_file_s.F90

@@ -26,10 +26,12 @@
 
   module procedure write_to_character_file_name
     integer file_unit, l
+    logical file_open
 
     call_assert(allocated(self%lines_))
 
-    open(newunit=file_unit, file=file_name, form='formatted', status='unknown', action='write')
+    inquire(file=file_name, opened=file_open, number=file_unit)
+    if (.not. file_open) open(newunit=file_unit, file=file_name, form='formatted', status='unknown', action='write')
 
     do l = 1, size(self%lines_)
       write(file_unit, '(a)') self%lines_(l)%string()