NAME

Coro - coroutine process abstraction

SYNOPSIS

 use Coro;

 async {
    # some asynchronous thread of execution
 };

 # alternatively create an async process like this:

 sub some_func : Coro {
    # some more async code
 }

 cede;

DESCRIPTION

This module collection manages coroutines. Coroutines are similar to Threads but don't run in parallel.

This module is still experimental, see the BUGS section below.

In this module, coroutines are defined as "callchain + lexical variables + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own callchain, it's own set of lexicals and it's own set of perl's most important global variables.

$main

This coroutine represents the main program.

$current (or as function: current)

The current coroutine (the last coroutine switched to). The initial value is $main (of course).

$idle

The coroutine to switch to when no other coroutine is running. The default implementation prints "FATAL: deadlock detected" and exits.

STATIC METHODS

Static methods are actually functions that operate on the current process only.

async { ... } [@args...]

Create a new asynchronous process and return it's process object (usually unused). When the sub returns the new process is automatically terminated.

   # create a new coroutine that just prints its arguments
   async {
      print "@_\n";
   } 1,2,3,4;

The coderef you submit MUST NOT be a closure that refers to variables in an outer scope. This does NOT work. Pass arguments into it instead.

schedule

Calls the scheduler. Please note that the current process will not be put into the ready queue, so calling this function usually means you will never be called again.

cede

"Cede" to other processes. This function puts the current process into the ready queue and calls schedule, which has the effect of giving up the current "timeslice" to other coroutines of the same or higher priority.

terminate

Terminates the current process.

Future versions of this function will allow result arguments.

# dynamic methods

PROCESS METHODS

These are the methods you can call on process objects.

new Coro \&sub [, @args...]

Create a new process and return it. When the sub returns the process automatically terminates. To start the process you must first put it into the ready queue by calling the ready method.

The coderef you submit MUST NOT be a closure that refers to variables in an outer scope. This does NOT work. Pass arguments into it instead.

$process->ready

Put the current process into the ready queue.

BUGS/LIMITATIONS

 - could be faster, especially when the core would introduce special
   support for coroutines (like it does for threads).
 - there is still a memleak on coroutine termination that I could not
   identify. Could be as small as a single SV.
 - this module is not well-tested.
 - if variables or arguments "disappear" (become undef) or become
   corrupted please contact the author so he cen iron out the
   remaining bugs.
 - this module is not thread-safe. You must only ever use this module from
   the same thread (this requirement might be loosened in the future to
   allow per-thread schedulers, but Coro::State does not yet allow this).

SEE ALSO

Coro::Channel, Coro::Cont, Coro::Specific, Coro::Semaphore, Coro::Signal, Coro::State, Coro::Event, Coro::RWLock, Coro::Handle, Coro::Socket.

AUTHOR

 Marc Lehmann <pcg@goof.com>
 http://www.goof.com/pcg/marc/