Expected behavior

Logger should be able to report operating system specific thread ID.

Actual behavior

The std native_handle is returned instead when using the %O Formatter parameter.

Steps to reproduce the problem

(please make this a SSCCE, if applicable and reasonable)
Add %O option to Foundation/samples/Logger/Logger.cpp and check output.

POCO version

develop as of 13 Sep 2018.

Compiler and version

gcc 5.4

Operating system and version

Ubuntu 16.04

Other relevant information

This used to work until the C++11 changes were merged in on 20 Sep 2017 and std::thread is used across all platforms.