Multithreaded Programming Guide

System Scope (Bound Threads)

PTHREAD_SCOPE_SYSTEM threads are created as bound threads. A bound thread is permanently attached to an LWP.

Each bound thread is bound to an LWP for the lifetime of the thread. This is equivalent to creating a Solaris thread in the THR_BOUND state. You can bind a thread to use special scheduling attributes with Realtime scheduling.

Note –

In neither case, bound or unbound, can a thread be directly accessed by or moved to another process.