> -----Original Message-----
> From: Chas Owens [mailto:[EMAIL PROTECTED]
> Sent: Thursday, June 14, 2007 12:10 PM
> To: Bob McConnell
> Cc: beginners@perl.org
> Subject: Re: Having trouble porting an application to MS-Windows
>
> On 6/14/07, Chas Owens <[EMAIL PROTECTED]> wrote:
> > On 6/14/07, Bob McConnell <[EMAIL PROTECTED]> wrote:
> > > In "perlport - Writing portable Perl" in the Alphabetic
> list of Perl
> > > Functions:
> > >
> > > alarm SECONDS
> > > alarm
> > > Not implemented. (Win32)
> > >
> > > I couldn't find anything in the ActiveState release notes that
> > > contradicted that.
> > snip
> > > > the latest version of ActiveState Perl on Windows XP works.
> > snip
> >
> > Are you using the latest version of ActiveState Perl? I
> installed the
> > latest version this morning to test the code I sent and when I run
> >
> > perldoc -T perlport | find /i alarm
> >
> > I get not output. The first three functions listed are -X,
> atan2, and binmode.
> >
>
> In fact, the reference to alarm drops out of perlport in version 5.8.3
> (released in 2004).
>
> from Perl 5.8.3's Changes file
> [ 21895]
> alarm() is now implemented on Win32.
>
I still can't get it to work, even without the fork. I am now running
ActivePerl 5.8.8.820 on Win2K SP4. Here are the code snippets after
pasting in the recommended alarm handling:
-----------------------------------
$port = 'COM4' unless $port;
$SIG{'INT'} = 'dokill'; # this allows me to kill it with
CTRL-Break
sub dokill {
kill 9,$child if $child;
}
sysopen( PORT, "$port", O_RDWR ) or die "Can't sysopen $port: $!";
binmode(PORT);
LINE: while (<IN>) { # Input records from input file.
chomp;
# loop on NAK or timeout with two retries
$done = 0;
$tries = 0;
do {
syswrite PORT, $_, length;
$timeout = 3;
eval {
local $SIG{ALRM} = sub { die "alarm\n" }; # NB:
\n required
alarm $timeout;
$nread = sysread PORT, $line, 1;
alarm 0;
};
if ($@) {
die unless $@ eq "alarm\n"; # propagate
unexpected errors
# timed out
print STDOUT " t/o";
}
else {
fprint STDOUT "sysread returned %d.\n", $nread;
if (ord $line == 21) {
print STDOUT " NAK";
}
if (ord $line == 6) {
print STDOUT " ACK";
$done = 1;
}
}
} while ($done == 0 && ++$tries < 3);
print STDOUT "\n";
if ($done == 0) {
next LINE;
}
#send response and wait for ACK/NAK here
}
-----------------------------------
This transmits the packet, but never comes out of the eval() if it
doesn't receive a character. Is there anything obvious that I missed?
Even if this does work, can I set simultaneous alarms in multiple
threads?
Thank you,
Bob McConnell
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