bug#23269: Multi-threaded operation, mbrtowc, and "untangle" script [was Re: bug#23269...]

[Paul Eggert]

Zev Weiss wrote:
> [Strictly speaking even in the default "single-threaded" mode it *is* in fact
> actually multi-threaded, but there's only one search thread, so output 
> ordering
> is unaffected.  In theory even this could allow a slight performance 
> improvement
> by overlapping pattern-matching with directory traversal and prefetching in 
> the
> master thread, but I'd guess it's probably negligible in most cases, and isn't
> really the goal of the patches.]

In the common case where a command like 'grep -r unusual' reads many files but
outputs few lines, I would think multiple search threads could work pretty well
even if the output is required to be deterministic.