Xref: utzoo comp.lang.c:40019 comp.unix.aix:5711
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!tahoe!bally!siva
From: siva@bally.Bally.COM (Siva Chelliah)
Newsgroups: comp.lang.c,comp.unix.aix
Subject: when to fflush ?
Keywords: fflush , fseek, fwrite
Message-ID: <504@bally.Bally.COM>
Date: 13 Jun 91 15:51:36 GMT
Distribution: usa
Organization: Bally systems
Lines: 36


Hi,
   I have a question.  Does seeking to the end of a file causes a flushing
of the buffer ? In my opinion it should not.
   Look at the following program.  Even though I write only 5 bytes, 
when you do a cat on test.out , you see "hello."  Move the sleep(500)
before fseek , and you won't see it.   It happened on both IBM RT running
AIX 2.1 and RS 6000 running AIX 3.1.  Please comment.

Thanks , 

Siva
------------------------------- 
#include <stdio.h>
main ()
{
	FILE *fp;
	char buf[80];
	strcpy(buf,"hello\n");
	system ("touch test.out");      /* just to create the file */
	fp = fopen ("test.out","r+");
	fseek(fp,0L,0);         /* seek to start of file - you do not need this */
	fwrite(buf,strlen(buf),1,fp);
	fseek(fp,0L,2);                 /* seek to end of file */
	sleep(500);
   fclose (fp);
}

	
	
  
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