i'm trying to jump out of an eval block if it takes too long to execute, so i've been searching for a way to signal an alarm on Win32.

the typical way to accomplish this is by using the perl alarm function. here's a simple example from section 5.6 of 'advanced perl programming:'

$SIG{ALRM} = \&timed_out;
eval {
    alarm (10);
    $buf = <>;
    alarm(0);           # Cancel the pending alarm if user responds.
};
if ($@ =~ /GOT TIRED OF WAITING/) {
    print "Timed out. Proceeding with default\n";
    ....
}

sub timed_out {
    die "GOT TIRED OF WAITING";
}

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this is all well an good for *NIX systems, but Win32 doesn't implement alarm. (see Alarm Implemented in Win32? for details.) curiously, Win32 does implement SIGALARM. consider:

C:\>perl -e "print join ' ', keys %SIG"
STOP NUM05 NUM06 ALRM NUM07 NUM24 NUM16 NUM17 NUM18 NUM19 ILL CHLD SEG
+V PIPE CLD
 ABRT CONT INT QUIT KILL BREAK TERM NUM01 FPE NUM10 NUM12

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yep, $SIG{ALRM} is a valid key in %SIG. but is it really?

i don't know enough about signals to be able to use a magic number or password to signal an ALRM. i don't know if it is even possible on Win32. if not, is there some other way for me to break out of an eval block before an operation has completed?

~Particle

In reply to ALRMing behavior on Win32 by particle

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