[Python-Dev] [Python-checkins] cpython: Close #12028: Make threading._get_ident() public, rename it to (original) (raw)

Charles-François Natali neologix at free.fr
Tue May 31 09:17:23 CEST 2011

+.. function:: getident() + +   Return the 'thread identifier' of the current thread.  This is a nonzero +   integer.  Its value has no direct meaning; it is intended as a magic cookie +   to be used e.g. to index a dictionary of thread-specific data.  Thread +   identifiers may be recycled when a thread exits and another thread is +   created. That's not quite true - the Thread id isn't relinquished until the Thread object itself is destroyed, rather than when the underlying thread finishes execution (i.e. the lifecycle of athread.ident is the same as that of id(athread)).

I'm not sure I understand, Nick. Since threads are started detached, their thread ID (e.g. returned by pthread_self() on pthreads) can be reused as soon as the underlying OS thread exits (i.e. returns from Modules/_threadmodule.c:t_boostrap) :

On a Linux kernel with NPTL:

$ cat /tmp/test.py import threading

def print_ident(): print(threading._get_ident())

t1 = threading.Thread(target=print_ident) t2 = threading.Thread(target=print_ident)

t1.start() t1.join()

t2.start() t2.join()

print(id(t1), id(t2)) $ ./python /tmp/test.py -1211954272 -1211954272 (3085561228L, 3083093028L)

I'm just curious, maybe I missed something?

Thanks,

cf

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