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From: phys169@csc.canterbury.ac.nz
Newsgroups: comp.lang.pascal
Subject: Re: soliciting advice (read/write mode in TP)
Message-ID: <1991May29.115336.905@csc.canterbury.ac.nz>
Date: 28 May 91 23:53:35 GMT
References: <1991May28.215118.541@javelin.sim.es.com>
Organization: University of Canterbury, Christchurch, New Zealand
Lines: 20

In article <1991May28.215118.541@javelin.sim.es.com>, tpehrson@javelin.sim.es.com (Tim Clinkenpeel) writes:
> is it possible to read and write a file at the same time or do i need to
> open the file for read, find the record, save the file pointer position,
> close the file, open the file for write, seek the pointer position and
> write the record -OR- is there a method which i am unware of (efficiency
> is what i seek).
> 
Little Known Facts of Turbo Pascal #60103:
When you use the "reset(somefile)" procedure in T.P., unless you put in a line
before like "filemode:=64;" then it actually opens the file for reading AND
WRITING. Some documentation suggests reset is for reading only, and rewrite for
writing; ignore it. You don't even need to muck around with fmInOut, its done
for you already.

Warning to Remember about T.P. number R850:
You can accidentally change data files you open with the reset procedure; it
doesn't stop you from writing to them.

Mark Aitchison, Physics, University of Canterbury, New Zealand.
Trivia Question: what do the numbers 60103 (or 4472) and R850 have in common?