Whenever GDB has to report an information about a thread, it uses a tuple with the following fields:
The global numeric id assigned to the thread by GDB. This field is always present.
Target-specific string identifying the thread. This field is always present.
Additional information about the thread provided by the target. It is supposed to be human-readable and not interpreted by the frontend. This field is optional.
Either ‘stopped’ or ‘running’, depending on whether the thread is presently running. This field is always present.
The value of this field is an integer number of the processor core the thread was last seen on. This field is optional.