process-run-function

process-run-function Function

Summary

Create a new process, passing it a function to run.

Package

Signature

process-run-function name keywords function &rest arguments => process

Arguments

`name`⇩	A name for the new process.
`keywords`⇩	Keywords specifying properties of the new process.
`function`⇩	A function to apply.
`arguments`⇩	Arguments to pass to `function`.

Values

process⇩

The newly created process.

Description

The function process-run-function creates a new Lisp process with name name. Other properties of process may be specified in keyword/value pairs in keywords:

`:priority`	A fixnum representing the priority for the process. If `:priority` is not supplied, the process priority becomes the value of the variable default-process-priority.
`:mailbox`	A mailbox, a string, `t` or `nil`, used to initialize the process-mailbox of `process`. True values specify that `process` should have a mailbox. A mailbox is used as-is; a string is used as the name of a new mailbox; and `t` causes it to create a mailbox with the same name as `process`, that is, `name`. Note that both process-send and process-wait-for-event force the relevant process to have a mailbox.
`:internal-server`	When true, this indicates that the process is an "internal server", which means that it responds to requests for work from other processes. The main effect of this is that if the only processes that remain are "internal servers", nothing is going to happen, so LispWorks quits. The system marks some of the processes that it creates as "internal server".
`:remote-terminator`	A function designator for a function of one argument.
`:local-terminator`	A function designator for a function of no arguments.
`:terminate-by-send`	A generalized boolean.

The new process is preset to apply function to arguments and runs in parallel, while process-run-function returns immediately.

:remote-terminator, :local-terminator or :terminate-by-send define the Terminate Method of the process, which is what process-terminate uses. If more than one of these keyword arguments is supplied, then :remote-terminator takes precedence over :local-terminator which takes precedence over :terminate-by-send.

If remote-terminator is supplied, it must be a function of one argument. When process-terminate is called, it funcalls remote-terminator on the process that process-terminate was called on, which normally will be another process. It should then terminate the process somehow. Typically the process itself will be frequently checking some flag which tells it to exit, and the function remote-terminator just sets this flag. remote-terminator should return non-nil when it is "successful", that is it did something that should cause the process to terminate. process-terminate checks the result of the call to remote-terminator, and if it is nil it also calls process-kill on the process.

If local-terminator is supplied, it must be a function of no arguments. When process-terminate is called it sends to the process a list with the local-terminator as the only element. That relies on the process itself processing what is sent to it and funcalling the function. This is what general-handle-event does, which is what system processes tend to use. In particular, all processes that are created by CAPI use it.

If terminate-by-send is supplied and non-nil, process-terminate sends the process a list containing current-process-kill (that is it is the same as :local-terminator 'current-process-kill). CAPI processes use this keyword.

Examples

CL-USER 253 > (defvar *stream* *standard-output*)
*STREAM*
 
CL-USER 254 > (mp:process-run-function 
               "My process" 
               '(:priority 42) 
               #'(lambda (x) 
                   (loop for i below x 
                         do (and (print i *stream*) 
                                 (sleep 1))
                         finally 
                         (print (mp:process-priority 
                                 mp:*current-process*) 
                                *stream*)))
               3)
#<MP:PROCESS Name "My process" Priority 850000 State "Running">
 
0 
1 
2 
42 
CL-USER 255 >