On 2008 Aug 31, at 10:44, Ganesh Sittampalam wrote:
On Sun, 31 Aug 2008, Brandon S. Allbery KF8NH wrote:
On 2008 Aug 31, at 10:34, Ganesh Sittampalam wrote:
I don't follow what you mean. stdin, stdout and stderr are just
file descriptors 0, 1 and 2, aren't they? You can create them as
many times as you want with using that information without causing
any confusion or conflict. Whereas the <- proposal has a "once-
only" requirement.
The convention is to provide buffered versions to improve the
performance of file I/O. These buffered filehandles must be
created once per runtime instance (and ideally once per process so
multiple runtimes don't find themselves overwriting each others'
output).
In that case it seems that any library that might be used from a
runtime that isn't the top-level of a process should avoid doing IO
to those handles, for fear of producing output corruption?
You handle it the same way you handle I/O with concurrency: either
one of the runtimes is "privileged" to the extent that it owns the
filehandles and other runtimes must make an inter-runtime call to use
them, or the filehandle structures include locking and are shared
across runtimes. Both of these are used in Haskell (see most GUI
libraries for the former, and the implementation of Handles for the
latter).
--
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED]
system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED]
electrical and computer engineering, carnegie mellon university KF8NH
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
