Libtask: a Coroutine Library for C and Unix

swtch.com

32 points·uriel··8 comments

There is also libcoro. In fact I think there's two of them ;-)

First is http://www.freebsdsoftware.org/devel/libcoro.html

Second is part of the excellent Coro Perl module: http://search.cpan.org/dist/Coro/

Libcoro's FreeBSD ports page claims to support i386 only, while Libtask supports i386, PowerPC, Sparc and ARM.

I think that is inaccurate, and probably based on the backend they are using: * -DCORO_ASM * Handcoded assembly, known to work only on a few architectures/ABI: GCC + x86/IA32 and amd64/x86_64 + GNU/Linux and a few BSDs.

The other backends use standard libc/SUSv2 calls like (get|set|swap)context, setjmp|longjmp and sigaltstack

If you're looking for something like this for Python, check out the greenlet library: http://pypi.python.org/pypi/greenlet

Very nice, I really like stackless and anyone writing concurrent code in python should use it.

It's unfortunate that he leaves channels until last and doesn't describe them fully. Understanding the benefits of structuring code to use channels is up there with other programming paradigms.

How does this compare to libevent and other NIO libs?

While libtask contains primitives for io (see fdread and other fd* functions) it uses poll() internally which does not scale well. And that is one of the problems that libevent solves by using the best available polling mechanism available. Libevent also provides timer and signal events while libtask does not.

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