GET_UNIT returns a free FORTRAN unit number.
Type | Intent | Optional | Attributes | Name | ||
---|---|---|---|---|---|---|
integer | :: | iunit |
subroutine get_unit ( iunit ) ! !******************************************************************************* ! !! GET_UNIT returns a free FORTRAN unit number. ! ! ! Discussion: ! ! A "free" FORTRAN unit number is an integer between 1 and 99 which ! is not currently associated with an I/O device. A free FORTRAN unit ! number is needed in order to open a file with the OPEN command. ! ! Modified: ! ! 02 March 1999 ! ! Author: ! ! John Burkardt ! ! Parameters: ! ! Output, integer IUNIT. ! ! If IUNIT = 0, then no free FORTRAN unit could be found, although ! all 99 units were checked (except for units 5 and 6). ! ! Otherwise, IUNIT is an integer between 1 and 99, representing a ! free FORTRAN unit. Note that GET_UNIT assumes that units 5 and 6 ! are special, and will never return those values. ! implicit none ! integer i integer ios integer iunit logical lopen iunit = 0 do i = 1, 99 if ( i /= 5 .and. i /= 6 ) then inquire ( unit = i, opened = lopen, iostat = ios ) if ( ios == 0 ) then if ( .not. lopen ) then iunit = i return end if end if end if end do return endsubroutine get_unit