Nodes of different colours represent the following:
Solid arrows point from a submodule to the (sub)module which it is descended from. Dashed arrows point from a module or program unit to modules which it uses.
program volatile_doctest use stringifor_string_t type(string) :: astring astring = 'Hello World! ' print "(L1)", astring%trim()==trim('Hello World! ') endprogram volatile_doctest