Sends an object to the mailbox of a given process.
process-send process object &key change-priority =>
process-send queues object in the mailbox of the given process.
object can any kind of Lisp object, and it is up to the receiving process to interpret it.
process-send only sends the event: it is the responsibility of the receiving process to actually read the event and then interpret it. Reading is typically done by calling process-wait-for-event. Interpreting the event is up the caller of process-wait-for-event. In the "standard" situation, for example in a process started by CAPI, the object will be processed as an event by calling general-handle-event.
process-send actually uses the process-mailbox of process, creating a mailbox for process if it does not already have one. In principle object can be read by another process, by calling mailbox-read (or process-wait-for-event) on the mailbox.
If change-priority, which has a default value of
:default, is non-nil, it controls how the priority of that process is calculated as follows:
fixnum -- use the value of change-priority as the new priority.
t -- set the priority to the interactive priority.
:default -- set the priority to the normal running priority.
LispWorks User Guide and Reference Manual - 13 Feb 2015