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] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH