setup-atomic-funcall Function

Summary

Sets up mutually atomic funcalls in SMP LispWorks.

Package

system

Signature

setup-atomic-funcall &rest function-and-arguments

Arguments

function-and-arguments⇩
	A list.

Description

The function setup-atomic-funcall sets up a funcall using function-and-arguments, which will be executed atomically with respect to any other calls which were also set up by setup-atomic-funcall.

Calling setup-atomic-funcall causes the execution of the form:

(apply (car function-and-arguments)
       (cdr function-and-arguments))

some time after the entry to setup-atomic-funcall. The call may happen before setup-atomic-funcall returns, and it is expected that normally this is what will happen. However, it may be delayed for an indefinite period, but normally this period is short (milliseconds). The execution occurs atomically with respect to other calls that were set up by setup-atomic-funcall.

The call should be short, because otherwise it will delay all the other calls. If an error occurs during the call, the atomicity is no longer guaranteed.

setup-atomic-funcall is useful when a process needs to atomically tell another process to do something, but does not need to wait for it to finish.

setup-atomic-funcall causes less congestion than using a lock, and so is more efficient for locks that may cause congestion. compare-and-swap and atomic-exchange operations will be faster.

See also

atomic-exchange
compare-and-swap