I've been working on a long running script that has to call some leaky libraries (which I do not control and can't fix) to do its job. "Simple enough", I think, "I'll segment out the leaky crud, put it a separate program. The main program spawns a child to process the data, gets the result and terminates the child when its done." Instant irrelevance to the leak, right? Wrong.

I've tried a number of things along the lines of:

open (my $SAVEDIN, '<&', STDIN ) or die "$!";
my ($READ, $WRITE);
pipe( $READ, $WRITE );
open ( STDIN, '<&', $READ ) or die "$!";

my $winproc;
Win32::Process::Create( 
    $winproc, 
    'C:\\perl\\bin\\perl.exe',
    'myscript.pl',
    1, # inherit handles
    '.'
) or die "Process did not start";

open( STDIN, '<&', $SAVEDIN ) or die "$!";
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The child process starts up fine. But the child does not inherit STDIN or STDOUT. I've tried localizing STDIN and STDOUT instead of overriding and restoring them manually.

I even tried an example from a very old TPJ (Fall 1997) article on the wonders of new and exciting Win32 Perl, and that does not work either. The child process does not inherit STDIO.

use Win32::Process; 

%Data = (     
    one   => 1,     
    two   => 2,     
    three => 3,
); 

pipe(READ, WRITE); 

select(WRITE); 
$| = 1; 
select(STDOUT); 

open(SAVEIN, "<&STDIN") || die "Can't save STDIN\n"; 
open(STDIN, "<&READ") || die "Can't redirect STDIN\n"; 

select(STDIN); 
$| = 1; 
select(STDOUT); 

Win32::Process::Create(
    $Process, 
    "c:\\perl\\bin\\perl.exe", 
    "tpjclient.pl", 
    1, NORMAL_PRIORITY_CLASS,
    "."
); 

open(STDIN, "<&SAVEIN"); 

close(SAVEIN); 
close(READ); 

print "$0: Sending variables to child...\n"; 

foreach $Temp (keys(%Data)){ 
    print "$0:\t$Temp=$Data{$Temp}\n"; 
        print WRITE "\$Data{$Temp}=$Data{$Temp};\n"; 
} 

print "$0: Finished sending variables.\n"; 

close(WRITE); 

print "$0: About to terminate. Waiting for <RETURN>...\n"; 

<STDIN>; 

print "$0: End.\n";
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print "$0: Starting.\n"; 
print "$0: Reading in variables...\n"; 

while(<STDIN>) { 
    eval($_); 
    print "$0: \t$_"; 
} 

print "$0: Finished reading variables.\n"; 
print "$0: Dumping variables...\n"; 
foreach $Temp (keys(%Data)){ 
    print "$0:\t$Temp=$Data{$Temp}\n"; 
} 
print "$0: End.\n";
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I'm using ActivePerl 5.8.8 on a WinXP SP3 system.

At this point I'll take any suggestions from "You idiot you forgot to do wibble, which it says in perlfoo", to "use a network socket".

It's worth mentioning that my goal is to integrate my solution with a Tk GUI. Since fileevent() is broken on Win32, I'll need to arrange for a non-blocking method of IO--any solution must work with select() or the O_NONBLOCK ioctl/fcntl flag--because I'll have to poll my child process while it is running. I've seen suggestions to use shared memory to pass data between Tk parent processes and their children. I have avoided using shared memory because of the cruddiness of the code I am sequestering--the last thing I need is a contagion of crap coming into my main program. Perhaps this is a baseless concern?