Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!tymix!cirrusl!ss168!dhesi
From: dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi)
Newsgroups: comp.lang.c
Subject: Re: fseek fread fwrite fflush
Message-ID: <3054@cirrusl.UUCP>
Date: 15 Apr 91 19:32:19 GMT
References: <1991Apr13.003817.12434@watdragon.waterloo.edu> <1991Apr12.194547.18080@hellgate.utah.edu> <188@bria.UUCP>
Sender: news@cirrusl.UUCP
Organization: Cirrus Logic Inc.
Lines: 22

Somebody writes:

     Certainly, a fflush() before a close is redundant.

Peculiar counterexample follows.

In an MS-DOS environment, to set the timestamp on a file, you must
first open it and get a file descriptor (file handle) to it.  So, if
you have just finished writing data to an open file and want to leave
its timestamp set to some special value, the safe sequence is:

     if (fflush(f) != 0) {
	handle error;
     }
     set_timestamp(fileno(f), time_value);
     (void) fclose(f);

If the fflush is not done, the fclose can write data to the file,
overriding the timestamp that has been set.
--
Rahul Dhesi <dhesi@cirrus.COM>
UUCP:  oliveb!cirrusl!dhesi