Re^5: win32 open3 strangeness (classic race, no fork)

The exact code looks like:

my( $write, $read, $error, $pid );
            if( $is_win32 )
            {
                print "here2\n";
                open my $file, "<", $_ or warn "Can't open $_ for read
+ing"; #log
                chomp( my $shebang = <$file> );
                close $file;
                
                warn "Bad shebang: $shebang - $_" unless $shebang =~ s
+/^\#!//; #log #shitty highlighting
                
                #warn "$shebang $_"; #log
                print "here 3\n";
                print "$shebang $_",$/;
                eval{ $pid = open3( $write, $read, $error, $shebang, $
+_ ) };
                print "here 4\n";
            }
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I have buffering turned off and when I run that snippet I get:

here2
here 3
perl usr/test.pl
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Where "perl usr/test.pl" is the $shebang $_ line. usr/test.pl looks like:

#!perl
print "x" x 489;
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If I change the 489 to 488, everything works perfectly. However, this is run from a forked subprocess, which is apparently causing the error, as when I run that open3 line from the command line via perl -e, it works perfectly, so theres something screwy with multiple forks.

For example, this command line invocation seems to (randomly?) hang D:\home\buu\pas>perl -le"use IPC::Open3 qw/open3/; fork; fork; print $$; open3($w, $r, $e, 'perl', 'usr/test.pl'); print <$r>" With test.pl being the same as I quoted above.

Comment on Re^5: win32 open3 strangeness (classic race, no fork) Select or Download Code

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Re^6: win32 open3 strangeness (no fork!) by tye (Sage) on Dec 16, 2004 at 00:59 UTC
Heh. demerphq was right after all. Using the emulated fork of Win32 Perl makes things very flakey (at least the last time I tried, which was after I was told "Oh, we fixed all those bugs" but it was still extremely buggy just like the previous few times when I heard "Oh, we fixed all those bugs"). Maybe it is only somewhat flakey now. But I would recommend you not use it. - tye	[reply]
Re^7: win32 open3 strangeness (no fork!) by BUU (Prior) on Dec 16, 2004 at 02:50 UTC
Is there anything I could use instead on win32? I'm working on a webserverish thing and I need to run CGI type scripts. Naturally I have no idea how long the script will take it what it might do so I can't block the entire server waiting for the CGI script to return, so naturally I turned to fork, but as you so rightly point out, it's flakey. As hell.	[reply]
Re^8: win32 open3 strangeness (no fork!) by tye (Sage) on Dec 16, 2004 at 03:02 UTC
Use one of the cpan modules that implements a network server and works on Win32. I believe there are several, but I haven't noticed reviews of any recently. - tye	[reply]