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

Replies are listed 'Best First'.
•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]

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