File contents not updated properly

balakrishnan has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: File contents not updated properly by dharanivasan (Scribe) on Dec 09, 2008 at 05:55 UTC
`use strict; use warnings; use FileHandle; open(FH,">Sample"); $\|=1; FH->autoflush(1); while(1) { print FH "This is for testing\n"; sleep 1; } close(FH);` [download]	[reply] [d/l]
Re: File contents not updated properly by sathiya.sw (Monk) on Dec 09, 2008 at 05:27 UTC
You need to select the file handle as, select(FH); `open(FH,">Sample"); select(FH); $\|=1; while(1) { print FH "This is for testing\n"; sleep 1; }` [download] Sathiyamoorthy	[reply] [d/l]
Re^2: File contents not updated properly by fmerges (Chaplain) on Dec 09, 2008 at 18:02 UTC
Hi, First of all, don't assume that you could open the file, check for it. Then use 3 argument open, and don't use a typeglob. `open my $fh, '>', $filename or die "Can't open $filename: $!";` [download] The solution provided will leave the default handler to be FH, which is not desired, meaning all prints, etc will use FH; alternatives: `# not so maintainable, but still used frequently select((select($fh), $\|++)[0]); # better use IO::Handle; $fh->autoflush(1);` [download] Check out the link about buffering provided... Regards, fmerges at irc.freenode.net	[reply] [d/l] [select]
Re: File contents not updated properly by apl (Monsignor) on Dec 09, 2008 at 11:37 UTC
You're Suffering from Buffering!	[reply]
Re: File contents not updated properly by Dhineshkumar (Initiate) on Jan 05, 2009 at 07:15 UTC
Using IO::Handle, We can flush the data whenever we need. Like below : use IO::Handle; open(FH,">Sample"); while(1) { print FH "This is for testing\n"; FH->flush(); sleep 1; }	[reply]
Re: File contents not updated properly by Dhineshkumar (Initiate) on Jan 05, 2009 at 07:18 UTC
When we are execute some commands in perl, Automatically file content got flush. Like below : open(FH,">Sample"); while(1) { print FH "This is for testing\n"; sleep 1; `date`; -- Sample command }	[reply]