No it doesn't return ENOSYS. Dyld calls abort() when a weak link is not resolved at the time of call.
-j On Thu, Oct 29, 2020 at 12:54 AM Stefan Hajnoczi <stefa...@gmail.com> wrote: > > On Wed, Oct 28, 2020 at 06:07:16PM -0700, Joelle van Dyne wrote: > > If built with Xcode 12 without the checks, a runtime error will occur. > > If that runtime error is ENOSYS then it's handled by existing code: > > if (preadv_present) { > nbytes = handle_aiocb_rw_vector(aiocb); > if (nbytes == aiocb->aio_nbytes || > (nbytes < 0 && nbytes != -ENOSYS)) { > goto out; > } > preadv_present = false; > } > > Why is additional code needed for iOS? > > Stefan