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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <config.h>
include <syserr.h>
include <fio.h>
# REOPEN -- Reopen a binary file. Used to gain two or more independent
# sets of buffers to access a binary file. No protection against two
# file descriptors trying to write to the same part of the file at the
# same time, which may result in loss of data. The file descriptors and
# buffers of reopened files are independent, but all files accessing the
# same channel share the same channel descriptor (necessary to synchronize
# i/o requests and to maintain a unique file size parameter).
int procedure reopen (fd, mode)
int fd, mode
pointer newfp, ffp
int newfd, fgetfd()
errchk syserr, malloc, seek
include <fio.com>
begin
ffp = fiodes[fd]
if (fd <= 0 || ffp == NULL)
call syserr (SYS_FILENOTOPEN)
if (FMODE(ffp) == READ_ONLY && mode != READ_ONLY)
call filerr (FNAME(ffp), SYS_FREOPNMODE)
if (FTYPE(ffp) != BINARY_FILE)
call filerr (FNAME(ffp), SYS_FREOPNTYPE)
newfd = fgetfd (FNAME(ffp), mode, BINARY_FILE)
newfp = fiodes[newfd]
FDEV(newfp) = FDEV(ffp)
FBUFSIZE(newfp) = FBUFSIZE(ffp)
FCHAN(newfp) = FCHAN(ffp)
# If this is the first reopen, allocate space for a separate channel
# descriptor and copy the channel descriptor from the original file.
if (FCD(ffp) == FLCD(ffp)) {
call malloc (FCD(ffp), LEN_CHANDES, TY_STRUCT)
call amovi (Memi[FLCD(ffp)], Memi[FCD(ffp)], LEN_CHANDES)
}
FREFCNT(ffp) = FREFCNT(ffp) + 1 # bump ref count
FCD(newfp) = FCD(ffp)
if (mode == APPEND)
call seek (newfd, EOFL)
return (newfd)
end
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