demo_system_readdir Program

     program demo_system_readdir
     use M_system, only : system_opendir,system_readdir
     use M_system, only : system_rewinddir,system_closedir
     use iso_c_binding
     implicit none

     type(c_ptr)                  :: dir
     character(len=:),allocatable :: filename
     integer                      :: i, ierr
     !--- open directory stream to read from
     call system_opendir('.',dir,ierr)
     if(ierr.eq.0)then
        !--- read directory stream twice
        do i=1,2
           write(*,'(a,i0)')'PASS ',i
           do
              call system_readdir(dir,filename,ierr)
              if(filename.eq.' ')exit
              write(*,*)filename
           enddo
           call system_rewinddir(dir)
        enddo
     endif
     !--- close directory stream
     call system_closedir(dir,ierr)

     end program demo_system_readdir