OpenEuphoria

Re: buffer flushing

• Posted by "Carl R. White" <C.R.White at SCM.BRAD.AC.UK> May 13, 1999
• 335 views

On Tue, 11 May 1999, Robert Craig wrote:

] Brian Jackson writes:
] > Does anyone know of a way to flush a file buffer
] > on an open file (other than closing and then re-opening it?)
]
] Closing the file is currently the only way.
] In the next major release I'll add a flush() routine.
]
] Regards,
]      Rob Craig

Here's an on-the-fly solution that uses the "close-reopen" trick. It's
coded so that it can be put straight into an .E library.

-- Initialise the trick:
sequence open_log
open_log = repeat(0,25) -- Or whatever Eu's MAX_FILES_LIMIT is...

-- redefine the open and close subroutines to use open_log:
function old_open(sequence name, sequence mode)
    return open(name, mode)
end function

procedure old_close(integer handle)
    close(handle)
end procedure

without warning -- me about redefinitions
    global function open(sequence name, sequence mode)
        integer handle
        handle = old_open(name, mode)
        if handle = -1 then return -1 end if

        open_log[handle] = {name, mode}

        return handle
    end function

    global procedure close(integer handle)
        if handle < 3 or handle > 25 or atom(open_log[handle]) then
            return
        end if
        open_log[handle] = 0
        old_close(handle)
    end procedure
with warning -- of other stuff :)

-- and now the new flush procedure:
global procedure flush(integer handle)
    object info
    if handle < 3 or handle > 25 then return end if
    info = open_log[handle]
    if atom(info) then return end if
    old_close(handle) -- use old close for speed, checks already done...
    if info[2][1] = 'r' then return end if -- only flush writeable files
    old_open(info[1], info[2]) -- using the new open isn't necessary.
end procedure

HTH,
Carl

--
Carl R White -- cyrek- at -bigfoot.com -- http://www.bigfoot.com/~cyrek
 aka Cyrek   --    No hyphens :)    --       Bigfoot URL Alias