Hmm... I may be screwed. Or not -- at least not yet. I can't really tell, since the evidence I currently have is ambiguous.
I found the following in PHP's online documentation:
Note:
It is currently impossible to register resource variables in a session. For example, you cannot create a connection to a database and store the connection id as a session variable and expect the connection to still be valid the next time the session is restored. PHP functions that return a resource are identified by having a return type of resource in their function definition. A list of functions that return resources are available in the resource types appendix.If $_SESSION (or $HTTP_SESSION_VARS for PHP 4.0.6 or less) is used, assign values to $_SESSION. For example: $_SESSION['var'] = 'ABC';
Now, what's ambiguous about this is that I found it in the documentation for the session_register() function, which I'm not using. It looks as though the final sentence of this note may be suggesting that $_SESSION will work where session_register() would fail, and I don't see any similar caveat in the documentation for $_SESSION. On the other hand, I would imagine that the same underlying mechanism for persisting a value between script invocations would be used in either case; and the fact that using $_SESSION for storing/retrieving a simple value like 'ABC' works for me, and using it for storing/retrieving a dio FD resource doesn't, leads me to believe that it's just not possible.
@colbec: have you been successful in persisting a dio FD resource via $_SESSION on your system?