Re^2: $? stuck returning -1...

Paul-

I'm confused. If it is supposed to set $?, then doesn't the sample program show that it's not working? My output looks like this:

exit1=0 ret1=Wed Jun 20 15:09:04 CDT 2007
24862: parent pid=24864
24864: child
exit2=-1 ret2=Wed Jun 20 15:09:04 CDT 2007
exit2=-1 ret2=Wed Jun 20 15:09:04 CDT 2007
exit2=-1 ret2=Wed Jun 20 15:09:04 CDT 2007
exit2=-1 ret2=Wed Jun 20 15:09:04 CDT 2007
exit2=-1 ret2=Wed Jun 20 15:09:04 CDT 2007
[download]

Thanks -Craig

Comment on Re^2: $? stuck returning -1... Download Code

Replies are listed 'Best First'.
Re^3: $? stuck returning -1... by Joost (Canon) on Jun 20, 2007 at 20:25 UTC
You're setting $SIG{CHLD} yourself so the wait() implicit in the backticks command will report there are no children. Set $SIG{CHLD} to undef before the foreach loop to see that that fixes the problem. update: $\|=1; my $ret1 = `date`; my $exit1 = $?; print STDERR "exit1=$exit1 ret1=$ret1"; $SIG{CHLD} = sub {print "Sigchld\n";wait}; foreach my $i (1..5) { my $ret2 = `date`; my $exit2 = $?; print STDERR "exit2=$exit2 ret2=$ret2"; } [download] output: `exit1=0 ret1=Wed Jun 20 22:29:13 CEST 2007 Sigchld exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007 Sigchld exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007 Sigchld exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007 Sigchld exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007 Sigchld exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007` [download] "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^3: $? stuck returning -1...
by Joost (Canon) on Jun 20, 2007 at 20:25 UTC

Set $SIG{CHLD} to undef before the foreach loop to see that that fixes the problem.

update:

$|=1;
my $ret1 = `date`;
my $exit1 = $?;
print STDERR "exit1=$exit1 ret1=$ret1";

$SIG{CHLD} = sub {print "Sigchld\n";wait};


foreach my $i (1..5) {
    my $ret2 = `date`;
    my $exit2 = $?;
    print STDERR "exit2=$exit2 ret2=$ret2";
}
[download]

exit1=0 ret1=Wed Jun 20 22:29:13 CEST 2007
Sigchld
exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007
Sigchld
exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007
Sigchld
exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007
Sigchld
exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007
Sigchld
exit2=-1 ret2=Wed Jun 20 22:29:13 CEST 2007
[download]

"What should it profit a man, if he should win a flame war, yet lose his cool?"

[reply]
[d/l]
[select]