Normally, later uses a global event loop for scheduling and running functions. However, in some cases, it is useful to create a private event loop to schedule and execute tasks without disturbing the global event loop. For example, you might have asynchronous code that queries a remote data source, but want to wait for a full back-and-forth communication to complete before continuing in your code -- from the caller's perspective, it should behave like synchronous code, and not do anything with the global event loop (which could run code unrelated to your operation). To do this, you would run your asynchronous code using a private event loop.
create_loop(parent = current_loop(), autorun = NULL)destroy_loop(loop)
exists_loop(loop)
current_loop()
with_temp_loop(expr)
with_loop(loop, expr)
global_loop()
The parent event loop for the one being created. Whenever the
parent loop runs, this loop will also automatically run, without having to
manually call run_now() on this loop. If NULL, then
this loop will not have a parent event loop that automatically runs it; the
only way to run this loop will be by calling run_now() on this
loop.
This exists only for backward compatibility. If set to
FALSE, it is equivalent to using parent=NULL.
A handle to an event loop.
An expression to evaluate.
create_loop creates and returns a handle to a private event loop,
which is useful when for scheduling tasks when you do not want to interfere
with the global event loop.
destroy_loop destroys a private event loop.
exists_loop reports whether an event loop exists -- that is, that it
has not been destroyed.
current_loop returns the currently-active event loop. Any calls to
later() or run_now() will use the current loop by
default.
with_loop evaluates an expression with a given event loop as the
currently-active loop.
with_temp_loop creates an event loop, makes it the current loop, then
evaluates the given expression. Afterwards, the new event loop is destroyed.
global_loop returns a handle to the global event loop.