On Sat, 4 May 2019 at 08:42, Andrew Roberts wrote: > 3) Stdlibc++ It's libstdc++.
> Release notes reference parallel algorithms requiring TBB 2018 or newer, > again guess work suggests this is Thread Building Blocks. It would be > nice to explicitly say that, and provide links to implementations. Yes, I'll improve that. > How is TBB detected and selected? I didn't see any configure switches > relating to this either in the toplevel configure or stdc++ configure It doesn't need to be detected during the build. It's only needed when compiling code that includes the new <execution> header and uses the new algos, so you just pass the necessary -I and -L options (if it's not installed in the usual search paths) and link with -ltbb (which is documented a couple of places in the libstdc++ manual). > files. Can it be built in tree etc? No, and it doesn't need to be, as it's not needed at build time. > Also while TBB may not be a prerequisite should it be at least > documented on that page: https://gcc.gnu.org/install/prerequisites.html > (or somewhere) > > The TBB release notes (written by Intel) seem to limit things to Intel > or compatible processors, wikipedia suggests a wider range (sparc?, > powerpc). Is ARM supported? Again it would be nice to document what > range of systems this can work on. Most of them. I don't really want our docs to be the place that's documented, as it's an external library. The plan is to provide an alternative backend for the algos, so there's an option to use them without TBB. That's work in progress though. For now if you want to use the new features, you need TBB.
