On Mar 24, 2021, Jonathan Wakely <jwak...@redhat.com> wrote:
> It should be impossible to have no random_device. As a fallback a
> pseudo random number generator should be used.
> If the default constructor throws then that suggests your target is
> misconfigured. Why isn't the mt19937 PRNG being used?
This is an x86_64-vx7r2 target, it has USE_RDRAND and USE_RDSEED both
enabled as the only RAND backends. AFAICT both of them fail their cpuid
tests, so _M_init falls through to the default, and throws.
I suppose we need to cover the case in which all of the compile-time
presumed-available random backends turn out to not be available at
run-time, and introduce an MT19937 dynamic fallback in the following
default: block, no?
default:
{ }
}
std::__throw_runtime_error(
__N("random_device::random_device(const std::string&):"
" device not available"));
> The 'random_device' effective-target is poorly named,
I see, thanks, I didn't think of checking its definition.
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Vim, Vi, Voltei pro Emacs -- GNUlius Caesar
