This is some freak-example how to use this feature to fork to a
bc-command on a Solaris-Server:
<?
$sockets=stream_socket_pair(STREAM_PF_UNIX,STREAM_SOCK_STREAM,
STREAM_IPPROTO_IP);
passthru('
perl -e \'
use strict; my ($x,@x);
open(STDIN,"-|","/bin/pfiles $$");
while (<>) { $x=$1 if(/^ +([0-9]+):/); push(@x,$x) if(/AF_UNIX/); }
print "Starting bc -l 0<&$x[1] 1>&$x[1] $x[0]<&- $x[0]>&- ...\n\n";
exec("bash","-c","bc -l 0<&$x[1] 1>&$x[1] $x[0]<&- $x[0]>&- &");\'');
fclose($sockets[0]);
fwrite($sockets[1],"666*999\n");
print "666*999 = ".fgets($sockets[1])."\n";
fwrite($sockets[1],"./696\n");
print "./696 = ".fgets($sockets[1])."\n";
fwrite($sockets[1],"quit\n");
fclose($sockets[1]);
?>
The big problem is, that there seems to be no way to obtain the real
filedescriptors of the two sockets, but you need them, if you want to
redirect some program's STDOUT and STDIN to one of these sockets.
I misused the /bin/pfiles command on a Solaris UNIX to find them.
Another (non-php-) problem is, that, if you use php in Apache, there
will be already a lot of open filedescriptors and the filedescriptors
of the sockets will be greater than 9. That's why I had to use the bash.
I think it is awful, but it works. Would be great, if someone
would come up with a better idea.