Interestingly enough, it seems you actually have to store the return value in order for your streams to exist. You can't throw it away.
In other words, this works:
<?php
$proc=proc_open("echo foo",
array(
array("pipe","r"),
array("pipe","w"),
array("pipe","w")
),
$pipes);
print stream_get_contents($pipes[1]);
?>
prints:
foo
but this doesn't work:
<?php
proc_open("echo foo",
array(
array("pipe","r"),
array("pipe","w"),
array("pipe","w")
),
$pipes);
print stream_get_contents($pipes[1]);
?>
outputs:
Warning: stream_get_contents(): <n> is not a valid stream resource in Command line code on line 1
The only difference is that in the second case we don't save the output of proc_open to a variable.
