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DateSun, 21 Jun 1998 10:39:13 -0400
FromJohn Kodis <>
SubjectRe: Thread implementations...
On Sat, Jun 20, 1998 at 01:49:50PM -0700, Dean Gaudet wrote:

> - let the kernel queue an event when the FD becomes ready.  So rather than
> calling poll() with a list of 100s of FDs, we tell the kernel on a per-FD
> basis "when this is ready for read/write queue an event on this pipe, and
> could you please hand me back this void * with it?  thanks".

Yow!  Shades of VMS!  This sounds very much like the VMS Async System
Trap mechanism that allowed you to perform a queued IO operation using
a call something like:

    status = sys$qio(
        READ_OPCODE, fd, buffer, sizeof(buffer),
        <lots of other parameters that I've long since forgotten>,
        ast_function, ast_parameter, ...);

The read would get posted, and when complete the ast_function would
get called with the ast_parameter in the context of the process that
posted the QIO.  This provided a powerful and easy-to-use method of
dealing with async IO.  It's one of the few VMS features that I wish
Unix supported.

-- John Kodis.

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