Re^5: Cannot catch ALRM signal for timeout

It still stuck, not alarmed for some reasons. My code right now has become:

sub process_scheme{
    my ($output_file) = @_;
    open (OUTPUT_FILE, ">", $output_file) || die "cannot open log file
+";
    my $scheme_pid = open (SCHEME, "./t.pl | ") || die "cannot pipe sc
+heme";
    my $str = "";
  MAIN:
    while (1) {
        eval{
            local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n require
+d
            alarm 5;#$allow_time;
            if (eof(SCHEME)){    
                close OUTPUT_FILE; close SCHEME;
                last MAIN;
            }
            $str = <SCHEME>;
            alarm 0;
        };
        if ($@) {
            close OUTPUT_FILE;
            kill $scheme_pid;
            close SCHEME;
            return -$current_player;
        }

        # process the line
        print OUTPUT_FILE $str;
    }
    return 1;
}
[download]

where the t.pl is

while(1){};
[download]

The script gets stuck, waiting forever, not stopping/returning anything

Comment on Re^5: Cannot catch ALRM signal for timeout Select or Download Code

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Re^6: Cannot catch ALRM signal for timeout by almut (Canon) on Dec 08, 2009 at 23:35 UTC
`kill $scheme_pid;` You probably meant something like `kill INT => $scheme_pid;` [download] As you have it, `kill` would try to send the signal number `$scheme_pid` to no processes — so nothing happens, effectively... As a result, your code hangs in the implicit `wait` behind `close SCHEME`, because the child process is still alive.	[reply] [d/l] [select]
Re^6: Cannot catch ALRM signal for timeout by ikegami (Patriarch) on Dec 08, 2009 at 22:45 UTC
what makes you think it's stuck? Are you sure it's really stuck and that you're not suffering from buffering? Add `OUTPUT_FILE->autoflush(1);` [download] after the `open`. You'll need `use IO::Handle qw( );` [download] at the top.	[reply] [d/l] [select]