Object sets are not available for use with file descriptors, as there are
only two operations possible on file descriptors: input and output.
Instead, a handler for either input or output can be registered with
system:serve-event for a specific file descriptor. Whenever any input
shows up, or output is possible on this file descriptor, the function
associated with the handler for that descriptor is funcalled with the
descriptor as it’s single argument.
This function installs and returns a new handler for the file
descriptor fd. direction can be either
the system should invoke the handler when input is available or
:output if the system should invoke the handler when output is
possible. This returns a unique object representing the handler,
and this is a suitable argument for
function must take one argument, the file descriptor.
This function removes handler, that
have previously returned.
This macro executes the supplied forms with a handler installed
using fd, direction, and function. See
system:add-fd-handler. The given forms are wrapped in an
unwind-protect; the handler is removed (see
system:remove-fd-handler) when done.
This function waits for up to timeout seconds for fd to
become usable for direction (either
:output). If timeout is
nil or unspecified, this
This function removes all handlers associated with fd. This
should only be used in drastic cases (such as I/O errors, but not
necessarily EOF). Normally, you should use
to remove the specific handler.