module testit

contains

subroutine test(fname)
implicit none


   character(len=*),intent(in) :: fname

   logical :: isOpened

   ! With the critical statements, there is no crash.
   ! Without the critical statements, a crash is likely of the loop is large.
   !!$OMP CRITICAL
   inquire(file=fname,opened=isOpened)
   !!$OMP END CRITICAL


end subroutine test

end module testit
!==================================================
program a
use omp_lib
use testit

implicit none

integer :: tid, i 
character(len=50) :: fname
  
  !$OMP PARALLEL PRIVATE(tid,i,fname)

  tid = OMP_get_thread_num()
  write(*,*) 'thread = ', tid


  write(fname,'(A,I2.2,A)') 'file_',tid,'.txt'

 
  !$OMP DO SCHEDULE(STATIC) 
     do i = 1,100000
        call test(fname)
     end do
  !$OMP END DO

  !$OMP END PARALLEL

  write(*,*) "FINISHED"


end program a