tell() on sysread()

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

I'm having problems getting tell() to return a value other than 0 after doing a sysread().

# in a loop after appropriate open
$bytes = sysread($self->{FH},$self->{buffer},1024);
print tell($self->{FH}),"\n";
[download]

$bytes is a lovely 1024, and there is good stuff in the buffer, but tell() is always returning 0; Is it my reference to a filehandle which works fine for sysread, but not for tell?

perlcapt
-ben

Update: merlyn explains why it doesn't work. The manual says to use sysseek(FH,0,1) which returns the offset just as implied. Problem understood and solved

Comment on tell() on sysread() Download Code

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•Re: tell() on sysread() by merlyn (Sage) on Oct 25, 2004 at 15:41 UTC
tell() is working with the buffer, but sysread() is bypassing the buffer. You need systell(), and if there isn't one, you're out of luck. {grin} -- Randal L. Schwartz, Perl hacker Be sure to read my standard disclaimer if this is a reply.	[reply]
Re^2: tell() on sysread() by Taulmarill (Deacon) on Oct 25, 2004 at 15:50 UTC
are you certain? beacuse the following works for me `perl -e'open FH,"<test.pl"\|\|die$!;$fh=\*FH;sysread($fh,$foo,256); $bar=tell($fh);print"$foo\n$bar\n";'` [download]	[reply] [d/l]
Re^3: tell() on sysread() by !1 (Hermit) on Oct 25, 2004 at 17:07 UTC
Yet it fails miserably on Win32. The side-effects of using sysread are system-specific.	[reply]