Re: Compiling libc/libstdc++ with concurrency support on Xtensa

[Alexey Neyman <stilor at att dot net>]

On 06/29/2017 12:29 AM, Jan Mrázek wrote:
> Hello guys,
>
> I tried to to contact you using IRC channel on freenode, however it 
> seems to be dead.
Yes, more or less.
> I have pthread implementation for xtensa processors and now I would 
> like to compile toolchain, libc and libstd++ with concurrency support 
> using pthreads (I wan to be able to use std::thread, std::mutex, 
> etc...). How can I do so using crosstool-ng? When I run ./ct-ng 
> menuconfig, there are no options to select concurrency implementation.

As far as I understand, libstdc++ depends on the underlying C library 
and the compiler to support multithreading [1]. Crosstool-NG does not 
offer a separate selection, but as far as I understand, libstdc++ should 
also be affected by CT_THREADS selection in the configuration.

What are you using as the C library? Newlib? Does it support threads? 
What does xtensa-*-gcc -v report for thread model?

I am not deeply familiar with libstdc++ internals, so I may be shooting 
for the easy targets that you're already covered.

Regards,
Alexey.

[1] https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_concurrency.html
> Could you help me please? All the documentation I found wasn't helpful 
> to deal with my issue.
>
> Jan 'yaqwsx' Mrázek