Re: generic q on freebsd
Kamal Prasad <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
Thanks. Why is it difficult to port the C++ runtime to the kernel? I mean what is the technological hurdle? thanks -kamal On Oct 6, 2020, at 10:53 PM, Warner Losh <[email protected]> wrote: > > On Tue, Oct 6, 2020, 11:03 AM Kamal R. Prasad <[email protected]> wrote: > >> hello, >> >> i am curious if it is possible to compile c++ code inside the freebsd >> kernel. >> > > > Possible? Yes, with restrictions. Easy? No. > > There are a number of restrictions on doing this. There is no C++ runtime > support provided in stock FreeBSD. You have to write your own, or find > someone else that has published theirs. And the code is likely to be > compiler dependent. People have done it and talked or blogged about it. > > Generally, if you don't use exceptions, templates, RTTI, expressions that > result in the automatic allocation of objects, have large objects (> 1k) on > the stack, etc, it may be possible. I tried it in the 90s and had to write > just a few routines to make simple classes work, but there's a lot of > dragons here and very little C++ code is written these days w/o reference > to the standard libraries, which aren't present in the kernel. > > Some googling turns up: > https://github.com/adamlsd/libcpp.ko from 6 years ago > https://lists.freebsd.org/pipermail/freebsd-arch/2018-June/019069.html has > some details from 2 years ago about command line args you might need. > > Many have tried. Few have succeeded. Those that have write all their code > to conform to a subset of the language. Few have had success moving C++ > code for other purposes into the kernel, though if it was written using the > proposed (but never ratified) eC++ (embedded subset), then chances are > greater. > > Good luck > > Warner > _______________________________________________ > [email protected] mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "[email protected]" _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-arm To unsubscribe, send any mail to "[email protected]"