getting channel errors

[Stephan Kountso <steplg@xxxxxxxxx>]

Many of channel_* functions return SSH_ERROR on error. But there is
exists only one function to get the reason of any errors:
ssh_get_error with only argument "ssh session", not channel.

So, my questions are:
1) how to handle ssh channel errors?
2) if also with ssh_get_error, then how about thread-safety? Multiply
threads on multiply channels cause corruption on ssh_get_error.

-- 
Best Regards,
Stephan Kountso aka StepLg