@mucephie
gtk-fortran does not include libadwaita. But if ever you are interested I could try to automatically generate Fortran/C interfaces to libadwaita and put them in a separate repository. Its dev files seem to follow the GTK style, so it should work rather well.
If you want to study the most modern Fortran features (OOP introduced in F2003, parallel computing introduced in F2008 and F2018...), see this book: https://www.manning.com/books/modern-fortran
@mucephie
gtk-fortran offers also interfaces to PLplot:
https://github.com/vmagnin/gtk-fortran/wiki/PLplot-integration
When I have time this week or next week, I will try to create a repository with libadwaita Fortran interfaces for experimentation.
@mucephie
I have just created a repository with experimental #Fortran interfaces for #libadwaita and #libsoup :
https://github.com/vmagnin/experimental_interfaces
More explanations are in the README.md file.
This repository contains experimental Fortran bindings for various C libraries, automatically generated with the cfwrapper program of the gtk-fortran project. - GitHub - vmagnin/experimental_interf...
@mucephie
If I have time, I may also try to reduce the number of errors next week.
Anyway, you can use for adw_application_new() an interface similar to:
function gtk_application_new(application_id, flags) bind(c)
import :: c_ptr, c_char, c_int
implicit none
type(c_ptr) :: gtk_application_new
character(kind=c_char), dimension(*) :: application_id
integer(c_int), value :: flags
end function