Newsgroups: comp.lang.fortran Path: utzoo!utgpu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!alchemy.chem.utoronto.ca!system From: system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson)) Subject: Re: Bug with file I/O? Message-ID: <1991Jan28.175145.26536@alchemy.chem.utoronto.ca> Organization: University of Toronto Chemistry Department References: <1991Jan24.145718.28686@alchemy.chem.utoronto.ca> <2136@travis.csd.harris.com> Distribution: comp Date: Mon, 28 Jan 1991 17:51:45 GMT In article <2136@travis.csd.harris.com> bill@hcx2.ssd.csd.harris.com (Bill Leonard) writes: >In article <1991Jan24.145718.28686@alchemy.chem.utoronto.ca>, system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson)) writes: >> As an aside, why not use binary/unformatted direct I/O; >> it is orders of magnitude faster than formatted I/O on all systems I >> have ever used? > >Beware! Unformatted I/O is not guaranteed to work if you mix data types. >Writing an INTEGER and reading a CHARACTER may give unpredictable results. I would not have just converted the program given to not use a FORMAT, I would also make it read/write only integers to the direct access file. While using A format on integers "works" on most systems, I wouldn't recommend it either, and mixing data types between the write and the read in unformatted I/O is almost a sure trip to disaster as Bill points out. -- Mike Peterson, System Administrator, U/Toronto Department of Chemistry E-mail: system@alchemy.chem.utoronto.ca Tel: (416) 978-7094 Fax: (416) 978-8775