Re^3: Ulimit makes program hang

Hi ,

I strongly suspect that, if you re-insert the sleep before shelling out, your results will be modified since the perl process won't otherwise have enough time to complete the print.

Have you tried the fork/exec approach ?

Have you tried an even lower limit and running the program using truss (or is it strace on linux) ?

As an afterthought, I do wonder if you've uncovered a bug in perl...

A user level that continues to overstate my experience :-))

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Re^4: Ulimit makes program hang by memo2005 (Initiate) on Aug 13, 2008 at 15:50 UTC
After insterting `sleep` before shelling out I get exactly same results. I'm not a system programmer to analyse `strace` output...sorry. I have tried `fork` and `exec` this way: `#!/usr/bin/perl -w my $x = $ARGV[0] + 1; print STDERR "$x\n"; if (!defined($child_pid = fork())) { die "cannot fork: $!"; } elsif ($child_pid) { waitpid($child_pid, 0); } else { exec "$0 $x"; }` [download] This program never hangs -- always says `cannot fork: Resource temporarily unavailable at ./fork_wait line 7`. But I must grab output of command so I can't use this solution.	[reply] [d/l]
Re^5: Ulimit makes program hang by Bloodnok (Vicar) on Aug 13, 2008 at 16:50 UTC
...as I suspected, using the evidence of your OP and this posting, I think you've got enough to raise a perl bug against the backtick (``) operator - I think it should `die` with a similar fatal error. Section 16 of the Perl Cookbook should provide you with some background in order to progress further with capturing output from a command ... HTH , A user level that continues to overstate my experience :-))	[reply] [d/l] [select]